1
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Schelling MPM, Verouden TWJ, Stevens TCM, Meijer JM. 3D visualization reveals the cooling rate dependent crystallization near a wall in dense microgel systems. SOFT MATTER 2024; 20:6343-6352. [PMID: 38963471 PMCID: PMC11323939 DOI: 10.1039/d4sm00517a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2024] [Accepted: 06/19/2024] [Indexed: 07/05/2024]
Abstract
Controlled crystallization, melting and vitrification are important fundamental processes in nature and technology. However, the microscopic details of these fundamental phenomena still lack understanding, in particular how the cooling rate and presence of a wall influence the crystal nucleation and glass formation. Thermoresponsive microgels provide the possibility to study phase transitions at the single-particle level, owing to the ability to tune the particle size with temperature. In this study, we employ composite microgels consisting of a hard core and a crosslinked poly(N-isopropyl acrylamide-co-methacrylic acid) shell to study the crystallization of dense suspensions of soft colloids near a wall using confocal microscopy. We investigate the effect of the cooling rate on the fluid-to-solid transition close to the sample wall. The structures formed during cooling range from glassy in the case of a rapid temperature quench to crystalline when a slow cooling rate is used. Detailed analysis of the final structure reveals that the cooling rate also sets the degree of alignment of the crystal domains with the wall as a result of a balance between homogeneous and heterogeneous crystal nucleation. The results presented here yield valuable insight into the microscopic details of temperature-controlled crystallization near a wall. This understanding will help pave the way towards optimal crystallization conditions for microgel applications.
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Affiliation(s)
- M P M Schelling
- Department of Applied Physics and Science Education, Eindhoven University of Technology, Groene Loper 19, 5612 AP Eindhoven, The Netherlands.
- Institute for Complex Molecular Systems, Eindhoven University of Technology, Groene Loper 19, 5612 AP Eindhoven, The Netherlands
| | - T W J Verouden
- Department of Applied Physics and Science Education, Eindhoven University of Technology, Groene Loper 19, 5612 AP Eindhoven, The Netherlands.
- Institute for Complex Molecular Systems, Eindhoven University of Technology, Groene Loper 19, 5612 AP Eindhoven, The Netherlands
| | - T C M Stevens
- Department of Applied Physics and Science Education, Eindhoven University of Technology, Groene Loper 19, 5612 AP Eindhoven, The Netherlands.
- Institute for Complex Molecular Systems, Eindhoven University of Technology, Groene Loper 19, 5612 AP Eindhoven, The Netherlands
| | - J-M Meijer
- Department of Applied Physics and Science Education, Eindhoven University of Technology, Groene Loper 19, 5612 AP Eindhoven, The Netherlands.
- Institute for Complex Molecular Systems, Eindhoven University of Technology, Groene Loper 19, 5612 AP Eindhoven, The Netherlands
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2
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Schelling MPM, Meijer JM. Controlled creation of point defects in three-dimensional colloidal crystals. Phys Rev E 2024; 109:L062601. [PMID: 39020982 DOI: 10.1103/physreve.109.l062601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Accepted: 05/06/2024] [Indexed: 07/20/2024]
Abstract
Crystal defects crucially influence the properties of crystalline materials and have been extensively studied. Even for the simplest type of defect-the point defect-however, basic properties such as their diffusive behavior, and their interactions, remain elusive on the atomic scale. Here, we demonstrate in situ control over the creation of isolated point defects in a three-dimensional (3D) colloidal crystal allowing insight on a single-particle level. Our system consists of thermoresponsive microgel particles embedded in a crystal of nonresponsive colloids. Heating this mixed-particle system triggers the shrinking of the embedded microgels, which then vacate their lattice positions, creating vacancy-interstitial pairs. We use temperature-controlled confocal laser scanning microscopy to verify and visualize the formation of the point defects. In addition, by reswelling the microgels we quantify the local lattice distortion around an interstitial defect. Our experimental model system provides a unique opportunity to shed light on the interplay between point defects, on the mechanisms of their diffusion, on their interactions, and on collective dynamics.
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3
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Dallari F, Lokteva I, Möller J, Roseker W, Goy C, Westermeier F, Boesenberg U, Hallmann J, Rodriguez-Fernandez A, Scholz M, Shayduk R, Madsen A, Grübel G, Lehmkühler F. Real-time swelling-collapse kinetics of nanogels driven by XFEL pulses. SCIENCE ADVANCES 2024; 10:eadm7876. [PMID: 38640237 PMCID: PMC11029799 DOI: 10.1126/sciadv.adm7876] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Accepted: 03/18/2024] [Indexed: 04/21/2024]
Abstract
Stimuli-responsive polymers are an important class of materials with many applications in nanotechnology and drug delivery. The most prominent one is poly-N-isopropylacrylamide (PNIPAm). The characterization of the kinetics of its change after a temperature jump is still a lively research topic, especially at nanometer-length scales where it is not possible to rely on conventional microscopic techniques. Here, we measured in real time the collapse of a PNIPAm shell on silica nanoparticles with megahertz x-ray photon correlation spectroscopy at the European XFEL. We characterize the changes of the particles diffusion constant as a function of time and consequently local temperature on sub-microsecond timescales. We developed a phenomenological model to describe the observed data and extract the characteristic times associated to the swelling and collapse processes. Different from previous studies tracking the turbidity of PNIPAm dispersions and using laser heating, we find collapse times below microsecond timescales and two to three orders of magnitude slower swelling times.
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Affiliation(s)
- Francesco Dallari
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany
- Department of Physics and Astronmy, University of Padua, Via Marzolo 8, 35131 Padova, Italy
| | - Irina Lokteva
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany
- The Hamburg Centre for Ultrafast Imaging, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Johannes Möller
- European X-Ray Free-Electron Laser Facility, Holzkoppel 4, 22869 Schenefeld, Germany
| | - Wojciech Roseker
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany
| | - Claudia Goy
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany
| | - Fabian Westermeier
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany
| | - Ulrike Boesenberg
- European X-Ray Free-Electron Laser Facility, Holzkoppel 4, 22869 Schenefeld, Germany
| | - Jörg Hallmann
- European X-Ray Free-Electron Laser Facility, Holzkoppel 4, 22869 Schenefeld, Germany
| | | | - Markus Scholz
- European X-Ray Free-Electron Laser Facility, Holzkoppel 4, 22869 Schenefeld, Germany
| | - Roman Shayduk
- European X-Ray Free-Electron Laser Facility, Holzkoppel 4, 22869 Schenefeld, Germany
| | - Anders Madsen
- European X-Ray Free-Electron Laser Facility, Holzkoppel 4, 22869 Schenefeld, Germany
| | - Gerhard Grübel
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany
- The Hamburg Centre for Ultrafast Imaging, Luruper Chaussee 149, 22761 Hamburg, Germany
- European X-Ray Free-Electron Laser Facility, Holzkoppel 4, 22869 Schenefeld, Germany
| | - Felix Lehmkühler
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany
- The Hamburg Centre for Ultrafast Imaging, Luruper Chaussee 149, 22761 Hamburg, Germany
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4
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Illing PE, Ono-Dit-Biot JC, Dalnoki-Veress K, Weeks ER. Compression and fracture of ordered and disordered droplet rafts. Phys Rev E 2024; 109:014610. [PMID: 38366516 DOI: 10.1103/physreve.109.014610] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Accepted: 12/06/2023] [Indexed: 02/18/2024]
Abstract
We simulate a two-dimensional array of droplets being compressed between two walls. The droplets are adhesive due to an attractive depletion force. As one wall moves toward the other, the droplet array is compressed and eventually induced to rearrange. The rearrangement occurs via a fracture, where depletion bonds are quickly broken between a subset of droplets. For monodisperse, hexagonally ordered droplet arrays, this fracture is preceded by a maximum force exerted on the walls, which drops rapidly after the fracture occurs. In small droplet arrays a fracture is a single well-defined event, but for larger droplet arrays, competing fractures can be observed. These are fractures nucleated nearly simultaneously in different locations. Finally, we also study the compression of bidisperse droplet arrays. The addition of a second droplet size further disrupts fracture events, showing differences between ideal crystalline arrays, crystalline arrays with a small number of defects, and fully amorphous arrays. These results are in good agreement with previously published experiments.
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Affiliation(s)
| | | | - Kari Dalnoki-Veress
- Department of Physics & Astronomy, McMaster University, Hamilton, Ontario, L8S 4L8, Canada
- Gulliver, CNRS UMR 7083, ESPCI Paris, University PSL, 75005 Paris, France
| | - Eric R Weeks
- Department of Physics, Emory University, Atlanta, Georgia 30322, USA
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5
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Xia Y, Yang X, Huang J, Liu R, Xu N, Yang M, Chen K. Orientational Order in Dense Colloidal Liquids and Glasses. PHYSICAL REVIEW LETTERS 2023; 131:128201. [PMID: 37802956 DOI: 10.1103/physrevlett.131.128201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 06/07/2023] [Accepted: 08/30/2023] [Indexed: 10/08/2023]
Abstract
We construct structural order parameters based on local angular and radial distribution functions in dense colloidal suspensions. All the order parameters show significant correlations to local dynamics in the supercooled and glass regime. In particular, the correlations between the orientational order and dynamical heterogeneity are consistently higher than those between the conventional two-body structural entropy and local dynamics. The structure-dynamics correlations can be explained by a excitation model with the energy barrier depending on local structural order. Our results suggest that in dense disordered packings, local orientational order is higher than translational order, and plays a more important role in determining the dynamics in glassy systems.
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Affiliation(s)
- Yiming Xia
- Beijing National Laboratory for Condensed Matter Physics and Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- University of Chinese Academy of Science, Beijing 100049, People's Republic of China
| | - Xiunan Yang
- Beijing National Laboratory for Condensed Matter Physics and Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- University of Chinese Academy of Science, Beijing 100049, People's Republic of China
| | - Junchao Huang
- Hefei National Research Center for Physical Sciences at the Microscale, CAS Key Laboratory of Microscale Magnetic Resonance and Department of Physics, University of Science and Technology of China, Hefei 230026, People's Republic of China
| | - Rui Liu
- Beijing National Laboratory for Condensed Matter Physics and Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- University of Chinese Academy of Science, Beijing 100049, People's Republic of China
| | - Ning Xu
- Hefei National Research Center for Physical Sciences at the Microscale, CAS Key Laboratory of Microscale Magnetic Resonance and Department of Physics, University of Science and Technology of China, Hefei 230026, People's Republic of China
| | - Mingcheng Yang
- Beijing National Laboratory for Condensed Matter Physics and Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- University of Chinese Academy of Science, Beijing 100049, People's Republic of China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, People's Republic of China
| | - Ke Chen
- Beijing National Laboratory for Condensed Matter Physics and Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- University of Chinese Academy of Science, Beijing 100049, People's Republic of China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, People's Republic of China
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6
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Hill A, Tanaka M, Aptowicz KB, Mishra CK, Yodh AG, Ma X. Depletion-driven antiferromagnetic, paramagnetic, and ferromagnetic behavior in quasi-two-dimensional buckled colloidal solids. J Chem Phys 2023; 158:2890481. [PMID: 37184019 DOI: 10.1063/5.0146155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Accepted: 04/10/2023] [Indexed: 05/16/2023] Open
Abstract
We investigate quasi-two-dimensional buckled colloidal monolayers on a triangular lattice with tunable depletion interactions. Without depletion attraction, the experimental system provides a colloidal analog of the well-known geometrically frustrated Ising antiferromagnet [Y. Han et al., Nature 456, 898-903 (2008)]. In this contribution, we show that the added depletion attraction can influence both the magnitude and sign of an Ising spin coupling constant. As a result, the nearest-neighbor Ising "spin" interactions can be made to vary from antiferromagnetic to para- and ferromagnetic. Using a simple theory, we compute an effective Ising nearest-neighbor coupling constant, and we show how competition between entropic effects permits for the modification of the coupling constant. We then experimentally demonstrate depletion-induced modification of the coupling constant, including its sign, and other behaviors. Depletion interactions are induced by rod-like surfactant micelles that change length with temperature and thus offer means for tuning the depletion attraction in situ. Buckled colloidal suspensions exhibit a crossover from an Ising antiferromagnetic to paramagnetic phase as a function of increasing depletion attraction. Additional dynamical experiments reveal structural arrest in various regimes of the coupling-constant, driven by different mechanisms. In total, this work introduces novel colloidal matter with "magnetic" features and complex dynamics rarely observed in traditional spin systems.
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Affiliation(s)
- Analisa Hill
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Michio Tanaka
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Kevin B Aptowicz
- Department of Physics and Engineering, West Chester University, West Chester, Pennsylvania 19383, USA
| | - Chandan K Mishra
- Discipline of Physics, Indian Institute of Technology (IIT) Gandhinagar, Palaj, Gujarat 382055, India
| | - A G Yodh
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Xiaoguang Ma
- Center for Complex Flows and Soft Matter Research, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
- Department of Physics, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
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7
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Crothers RA, Orr NHP, van der Meer B, Dullens RPA, Yanagishima T. Characterization and Optimization of Fluorescent Organosilica Colloids for 3D Confocal Microscopy Prepared Under "Zero-Flow" Conditions. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:5306-5314. [PMID: 37021809 DOI: 10.1021/acs.langmuir.2c03306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
We optimize and characterize the preparation of 3-trimethoxysilyl propyl methacrylate (TPM) colloidal suspensions for three-dimensional confocal microscopy. We revisit a simple synthesis of TPM microspheres by nucleation of droplets from prehydrolyzed TPM oil in a "zero-flow" regime and demonstrate how precise and reproducible control of particle size may be achieved via single-step nucleation with a focus on how the reagents are mixed. We also revamp the conventional dyeing method for TPM particles to achieve uniform transfer of a fluorophore to the organosilica droplets, improving particle identification. Finally, we illustrate how a ternary mixture of tetralin, trichloroethylene, and tetrachloroethylene may be used as a suspension medium which matches the refractive index of these particles while allowing independent control of the density mismatch between particle and solvent.
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Affiliation(s)
- Ruth A Crothers
- Institute for Molecules and Materials, Radboud University Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - Nicholas H P Orr
- Laboratoire Charles Coulomb UMR 5221, Université de Montpellier, F-34095 Montpellier, France
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - Berend van der Meer
- Institute for Molecules and Materials, Radboud University Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - Roel P A Dullens
- Institute for Molecules and Materials, Radboud University Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - Taiki Yanagishima
- Department of Physics, Graduate School of Science, Kyoto University, Kyoto 606-8224, Japan
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
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8
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Saisavadas MV, Dhara S, Joshi RG, Tata BVR. Large amplitude oscillatory shear studies on dense PNIPAM microgel colloidal glasses. Colloid Polym Sci 2023. [DOI: 10.1007/s00396-023-05096-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/05/2023]
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9
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Liu W, Zhu Y, Li Y, Han J, Ngai T. Unveiling the structural relaxation of microgel suspensions at hydrophilic and hydrophobic interfaces. J Colloid Interface Sci 2023; 633:948-958. [PMID: 36509038 DOI: 10.1016/j.jcis.2022.11.150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 11/24/2022] [Accepted: 11/29/2022] [Indexed: 12/12/2022]
Abstract
HYPOTHESIS Poly(N-isopropylacrylamide) (PNIPAM) microgel particles show considerable hydrophilicity below the lower critical solution temperature (LCST) while they become hydrophobic above LCST. We hypothesize that interfacial wettability could tune particle-surface interaction and subsequent structural relaxation of microgel suspensions at interfaces during the volume phase transition. EXPERIMENTS The evanescent-wave scattering images of microgels at hydrophilic and hydrophobic interfaces are analyzed by a density-fluctuation autocorrelation function (δACF) over a wide range of particle volume fraction ϕ. The structural relaxation is characterized by the decay behavior of δACF. The scattering images in bulk are also processed as a comparison. FINDINGS A two-step relaxation decay is observed at both hydrophilic and hydrophobic interfaces. Relative to fast decay, the rate of structural relaxation in slow decay is reduced by a factor of ∼ 500 and ∼ 50 at hydrophilic and hydrophobic interfaces, respectively. The relaxation times obey divergent power-law dependences on intermediate regime of observing length scales at the two interfaces. Besides, the distribution of fluctuation for relaxation time at different local regions reveals that the structural relaxation is much more homogenous at hydrophilic interfaces than that at hydrophobic interfaces, especially at high ϕ.
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Affiliation(s)
- Wei Liu
- The Key Laboratory of Synthetic and Biological Colloids, Ministry of Education & School of Chemical and Material Engineering, Jiangnan University, Wuxi 214122, China
| | - Yuwei Zhu
- Department of Chemistry, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, China
| | - Yinan Li
- Department of Chemistry, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, China
| | - Jie Han
- School of Science and Technology, Hong Kong Metropolitan University, Homantin, Kowloon, Hong Kong, China.
| | - To Ngai
- The Key Laboratory of Synthetic and Biological Colloids, Ministry of Education & School of Chemical and Material Engineering, Jiangnan University, Wuxi 214122, China; Department of Chemistry, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, China.
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10
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Shaulli X, Rivas-Barbosa R, Bergman MJ, Zhang C, Gnan N, Scheffold F, Zaccarelli E. Probing Temperature Responsivity of Microgels and Its Interplay with a Solid Surface by Super-Resolution Microscopy and Numerical Simulations. ACS NANO 2023; 17:2067-2078. [PMID: 36656959 PMCID: PMC9933603 DOI: 10.1021/acsnano.2c07569] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 01/12/2023] [Indexed: 06/17/2023]
Abstract
Super-resolution microscopy has become a powerful tool to investigate the internal structure of complex colloidal and polymeric systems, such as microgels, at the nanometer scale. An interesting feature of this method is the possibility of monitoring microgel response to temperature changes in situ. However, when performing advanced microscopy experiments, interactions between the particle and the environment can be important. Often microgels are deposited on a substrate, since they have to remain still for several minutes during the experiment. This study uses direct stochastic optical reconstruction microscopy (dSTORM) and advanced coarse-grained molecular dynamics simulations to investigate how individual microgels anchored on hydrophilic and hydrophobic surfaces undergo their volume phase transition with temperature. We find that, in the presence of a hydrophilic substrate, the structure of the microgel is unperturbed and the resulting density profiles quantitatively agree with simulations performed under bulk conditions. Instead, when a hydrophobic surface is used, the microgel spreads at the interface and an interesting competition between the two hydrophobic strengths,monomer-monomer vs monomer-surface,comes into play at high temperatures. The robust agreement between experiments and simulations makes the present study a fundamental step to establish this high-resolution monitoring technique as a platform for investigating more complex systems, these being either macromolecules with peculiar internal structure or nanocomplexes where molecules of interest can be encapsulated in the microgel network and controllably released with temperature.
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Affiliation(s)
- Xhorxhina Shaulli
- Department
of Physics, University of Fribourg, Chemin du Musée 3, 1700Fribourg, Switzerland
| | - Rodrigo Rivas-Barbosa
- Department
of Physics, Sapienza University of Rome, Piazzale Aldo Moro 2, 00185Roma, Italy
| | - Maxime J. Bergman
- Department
of Physics, University of Fribourg, Chemin du Musée 3, 1700Fribourg, Switzerland
| | - Chi Zhang
- Department
of Physics, University of Fribourg, Chemin du Musée 3, 1700Fribourg, Switzerland
| | - Nicoletta Gnan
- Department
of Physics, Sapienza University of Rome, Piazzale Aldo Moro 2, 00185Roma, Italy
- CNR
Institute of Complex Systems, Uos Sapienza, Piazzale Aldo Moro 2, 00185Roma, Italy
| | - Frank Scheffold
- Department
of Physics, University of Fribourg, Chemin du Musée 3, 1700Fribourg, Switzerland
| | - Emanuela Zaccarelli
- Department
of Physics, Sapienza University of Rome, Piazzale Aldo Moro 2, 00185Roma, Italy
- CNR
Institute of Complex Systems, Uos Sapienza, Piazzale Aldo Moro 2, 00185Roma, Italy
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11
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Fussell SL, Royall CP, van Duijneveldt JS. Controlling Kinetic Pathways in Demixing Microgel-Micelle Mixtures. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:1010-1018. [PMID: 36621908 PMCID: PMC9878723 DOI: 10.1021/acs.langmuir.2c02583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 12/22/2022] [Indexed: 06/17/2023]
Abstract
We investigate the temperature-dependent phase behavior of mixtures of poly(N-isopropylacrylamide) (pNIPAM) microgel colloids and a triblock copolymer (PEO-PPO-PEO) surfactant. Usually, gelation in these systems results from an increase in temperature. Here we investigate the role of the heating rate, and surprisingly, we find that this causes the mechanism of aggregation to change from one which is driven by depletion of the microgels by the micelles at low temperatures to the association of the two species at high temperatures. We thus reveal two competing mechanisms for attractions between the microgel particles which can be controlled by changing the heating rate. We use this heating-rate-dependent response of the system to access multiple structures for the same system composition. Samples were found to demix into phases rich and poor in microgel particles at temperatures below 33 °C, under conditions where the microgels particles are partially swollen. Under rapid heating full demixing is bypassed, and gel networks are formed instead. The temperature history of the sample, therefore, allows for kinetic selection between different final structures, which may be metastable.
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Affiliation(s)
- S. L. Fussell
- School
of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, U.K.
- Bristol
Centre for Functional Nanomaterials, University
of Bristol, Tyndall Avenue, Bristol BS8 1TL, U.K.
| | - C. P. Royall
- School
of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, U.K.
- Bristol
Centre for Functional Nanomaterials, University
of Bristol, Tyndall Avenue, Bristol BS8 1TL, U.K.
- Gulliver
UMR CNRS 7083, ESPCI Paris, Université
PSL, 75005 Paris, France
- HH
Wills Physics Laboratory, University of
Bristol, Tyndall Avenue, Bristol BS8 1TL, U.K.
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12
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Yang Y, Sha L, Zhao H, Guo Z, Wu M, Lu P. Recent advances in cellulose microgels: Preparations and functionalized applications. Adv Colloid Interface Sci 2023; 311:102815. [PMID: 36427465 DOI: 10.1016/j.cis.2022.102815] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 11/02/2022] [Accepted: 11/15/2022] [Indexed: 11/20/2022]
Abstract
Microgels are soft, deformable, permeable, and stimuli-responsive microscopic polymeric particles that are now emerging as prospective multifunctional soft materials for delivery systems, interface stabilization, cell cultures and tissue engineering. Cellulose microgels are emerging biopolymeric microgels with unique characteristics such as abound hydroxyl structure, admirable designability, multiscale pore network and excellent biocompatibility. This review summarizes the fabrication strategies for microgel, then highlights the fabrication routes for cellulose microgels, and finally elaborates cellulose microgels' bright application prospects with unique characteristics in the fields of controlled release, interface stabilization, coating, purification, nutrition/drug delivery, and bio-fabrication. The challenges to be addressed for further applications and considerable scope for development in future of cellulose microgels are also discussed.
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Affiliation(s)
- Yang Yang
- College of Light Industry and Food Engineering, Guangxi Key Laboratory of Clean Pulp and Papermaking and Pollution Control, Guangxi University, Nanning, Guangxi 530004, China
| | - Lishan Sha
- College of Light Industry and Food Engineering, Guangxi Key Laboratory of Clean Pulp and Papermaking and Pollution Control, Guangxi University, Nanning, Guangxi 530004, China
| | - Han Zhao
- College of Light Industry and Food Engineering, Guangxi Key Laboratory of Clean Pulp and Papermaking and Pollution Control, Guangxi University, Nanning, Guangxi 530004, China
| | - Zhaojun Guo
- College of Light Industry and Food Engineering, Guangxi Key Laboratory of Clean Pulp and Papermaking and Pollution Control, Guangxi University, Nanning, Guangxi 530004, China
| | - Min Wu
- College of Light Industry and Food Engineering, Guangxi Key Laboratory of Clean Pulp and Papermaking and Pollution Control, Guangxi University, Nanning, Guangxi 530004, China
| | - Peng Lu
- College of Light Industry and Food Engineering, Guangxi Key Laboratory of Clean Pulp and Papermaking and Pollution Control, Guangxi University, Nanning, Guangxi 530004, China.
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13
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Dichotomous behaviors of stress and dielectric relaxations in dense suspensions of swollen thermoreversible hydrogel microparticles. J Colloid Interface Sci 2023; 630:223-231. [DOI: 10.1016/j.jcis.2022.10.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 09/29/2022] [Accepted: 10/01/2022] [Indexed: 11/05/2022]
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14
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Stubley SJ, Cayre OJ, Murray BS, Celigueta Torres I. Pectin-based microgels for rheological modification in the dilute to concentrated regimes. J Colloid Interface Sci 2022; 628:684-695. [DOI: 10.1016/j.jcis.2022.07.147] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2022] [Revised: 06/14/2022] [Accepted: 07/23/2022] [Indexed: 11/25/2022]
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15
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Buratti E, Tavagnacco L, Zanatta M, Chiessi E, Buoso S, Franco S, Ruzicka B, Angelini R, Orecchini A, Bertoldo M, Zaccarelli E. The role of polymer structure on water confinement in poly(N-isopropylacrylamide) dispersions. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.118924] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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16
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Behra JS, Thiriez A, Truzzolillo D, Ramos L, Cipelletti L. Controlling the volume fraction of glass-forming colloidal suspensions using thermosensitive host "mesogels". J Chem Phys 2022; 156:134901. [PMID: 35395903 DOI: 10.1063/5.0086822] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The key parameter controlling the glass transition of colloidal suspensions is φ, the fraction of the sample volume occupied by the particles. Unfortunately, changing φ by varying an external parameter, e.g., temperature T as in molecular glass formers, is not possible, unless one uses thermosensitive colloidal particles, such as the popular poly(N-isopropylacrylamide) (PNiPAM) microgels. These, however, have several drawbacks, including high deformability, osmotic deswelling, and interpenetration, which complicate their use as a model system to study the colloidal glass transition. Here, we propose a new system consisting of a colloidal suspension of non-deformable spherical silica nanoparticles, in which PNiPAM hydrogel spheres of ∼100-200μm size are suspended. These non-colloidal "mesogels" allow for controlling the sample volume effectively available to the silica nanoparticles and hence their φ, thanks to the T-induced change in mesogels' volume. Using optical microscopy, we first show that the mesogels retain their ability to change size with T when suspended in Ludox suspensions, similarly as in water. We then show that their size is independent of the sample thermal history such that a well-defined, reversible relationship between T and φ may be established. Finally, we use space-resolved dynamic light scattering to demonstrate that, upon varying T, our system exhibits a broad range of dynamical behaviors across the glass transition and beyond, comparable with those exhibited by a series of distinct silica nanoparticle suspensions of various φ.
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Affiliation(s)
- J S Behra
- Laboratoire Charles Coulomb (L2C), Université Montpellier, CNRS, Montpellier, France
| | - A Thiriez
- Laboratoire Charles Coulomb (L2C), Université Montpellier, CNRS, Montpellier, France
| | - D Truzzolillo
- Laboratoire Charles Coulomb (L2C), Université Montpellier, CNRS, Montpellier, France
| | - L Ramos
- Laboratoire Charles Coulomb (L2C), Université Montpellier, CNRS, Montpellier, France
| | - L Cipelletti
- Laboratoire Charles Coulomb (L2C), Université Montpellier, CNRS, Montpellier, France
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17
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Rivas-Barbosa R, Ruiz-Franco J, Lara-Peña MA, Cardellini J, Licea-Claverie A, Camerin F, Zaccarelli E, Laurati M. Link between Morphology, Structure, and Interactions of Composite Microgels. Macromolecules 2022; 55:1834-1843. [PMID: 35283539 PMCID: PMC8908736 DOI: 10.1021/acs.macromol.1c02171] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Revised: 01/19/2022] [Indexed: 11/28/2022]
Abstract
We combine small-angle scattering experiments and simulations to investigate the internal structure and interactions of composite poly(N-isopropylacrylamide)-poly(ethylene glycol) (PNIPAM-PEG) microgels. At low temperatures the experimentally determined form factors and the simulated density profiles indicate a loose internal particle structure with an extended corona that can be modeled as a starlike object. With increasing temperature across the volumetric phase transition, the form factor develops an inflection that, using simulations, is interpreted as arising from a conformation in which PEG chains are incorporated in the interior of the PNIPAM network. This gives rise to a peculiar density profile characterized by two dense, separated regions, at odds with configurations in which the PEG chains reside on the surface of the PNIPAM core. The conformation of the PEG chains also have profound effects on the interparticle interactions: Although chains on the surface reduce the solvophobic attraction typically experienced by PNIPAM particles at high temperatures, PEG chains inside the PNIPAM network shift the onset of attractive interaction at even lower temperatures. Our results show that by tuning the morphology of the composite microgels, we can qualitatively change both their structure and their mutual interactions, opening the way to explore new collective behaviors of these objects.
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Affiliation(s)
- Rodrigo Rivas-Barbosa
- Department
of Physics, Sapienza University of Rome, Piazzale Aldo Moro 2, 00185 Roma, Italy
- División
de Ciencias e Ingenierías, Universidad
de Guanajuato, Lomas del Bosque 103, 37150 León, Mexico
| | - José Ruiz-Franco
- Department
of Physics, Sapienza University of Rome, Piazzale Aldo Moro 2, 00185 Roma, Italy
- CNR
Institute of Complex Systems, Uos Sapienza, Piazzale Aldo Moro 2, 00185 Roma, Italy
- Physical
Chemistry and Soft Matter, Wageningen University
& Research, Stippeneng 4, 6708WE Wageningen, The Netherlands
| | - Mayra A. Lara-Peña
- División
de Ciencias e Ingenierías, Universidad
de Guanajuato, Lomas del Bosque 103, 37150 León, Mexico
| | - Jacopo Cardellini
- Dipartimento
di Chimica and CSGI, Universitá di
Firenze, 50019 Sesto Fiorentino, Italy
| | - Angel Licea-Claverie
- Centro
de Graduados e Investigación en Química del Tecnológico
Nacional de México, Instituto Tecnológico
de Tijuana, 22500 Tijuana, Mexico
| | - Fabrizio Camerin
- Department
of Physics, Sapienza University of Rome, Piazzale Aldo Moro 2, 00185 Roma, Italy
- CNR
Institute of Complex Systems, Uos Sapienza, Piazzale Aldo Moro 2, 00185 Roma, Italy
| | - Emanuela Zaccarelli
- Department
of Physics, Sapienza University of Rome, Piazzale Aldo Moro 2, 00185 Roma, Italy
- CNR
Institute of Complex Systems, Uos Sapienza, Piazzale Aldo Moro 2, 00185 Roma, Italy
| | - Marco Laurati
- Dipartimento
di Chimica and CSGI, Universitá di
Firenze, 50019 Sesto Fiorentino, Italy
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18
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Vialetto J, Nussbaum N, Bergfreund J, Fischer P, Isa L. Influence of the interfacial tension on the microstructural and mechanical properties of microgels at fluid interfaces. J Colloid Interface Sci 2022; 608:2584-2592. [PMID: 34774321 DOI: 10.1016/j.jcis.2021.10.186] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 10/21/2021] [Accepted: 10/29/2021] [Indexed: 10/19/2022]
Abstract
Microgels are soft colloidal particles constituted by cross-linked polymer networks with a high potential for applications. In particular, after adsorption at a fluid interface, interfacial tension provides two-dimensional (2D) confinement for microgel monolayers and drives the reconfiguration of the particles, enabling their deployment in foam and emulsion stabilization and in surface patterning for lithography, sensing and optical materials. However, most studies focus on systems of fluids with a high interfacial tension, e.g. alkanes/ or air/water interfaces, which imparts similar properties to the assembled monolayers. Here, instead, we compare two organic fluid phases, hexane and methyl tert-butyl ether, which have markedly different interfacial tension (γ) values with water and thus tune the deformation of adsorbed microgels. We rationalize how γ controls the single-particle morphology, which consequently modulates the structural and mechanical response of the monolayers at varying interfacial compression. Specifically, when γ is low, the microgels are less deformed within the interface plane and their polymer networks can rearrange more easily upon lateral compression, leading to softer monolayers. Selecting interfaces with different surface energy offers an additional control to customize the 2D assembly of soft particles, from the fine-tuning of particle size and interparticle spacing to the tailoring of mechanical properties.
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Affiliation(s)
- Jacopo Vialetto
- Laboratory for Soft Materials and Interfaces, Department of Materials, ETH Zürich, Vladimir-Prelog-Weg 5, 8093 Zürich, Switzerland.
| | - Natalie Nussbaum
- Institute of Food, Nutrition and Health, ETH Zürich, Schmelzbergstrasse 7, 8092 Zürich, Switzerland
| | - Jotam Bergfreund
- Institute of Food, Nutrition and Health, ETH Zürich, Schmelzbergstrasse 7, 8092 Zürich, Switzerland
| | - Peter Fischer
- Institute of Food, Nutrition and Health, ETH Zürich, Schmelzbergstrasse 7, 8092 Zürich, Switzerland
| | - Lucio Isa
- Laboratory for Soft Materials and Interfaces, Department of Materials, ETH Zürich, Vladimir-Prelog-Weg 5, 8093 Zürich, Switzerland.
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19
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Bomont JM, Likos CN, Hansen JP. Glass quantization of the Gaussian core model. Phys Rev E 2022; 105:024607. [PMID: 35291117 DOI: 10.1103/physreve.105.024607] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Accepted: 02/07/2022] [Indexed: 06/14/2023]
Abstract
We use the replica method to study the dynamical glass transition of the Gaussian core model, a system of ultrasoft repulsive spheres interacting via a Gaussian potential, focusing on low temperatures and low-to-moderate densities. At constant temperature, an amorphous glassy state is entered upon a first compression but this glass melts as the density is further increased. In addition to this reentrant transition, a second, smooth transition is discovered between a continuous and a discretized glass. The properties of the former are continuous functions of temperatures, whereas the latter exhibits a succession of stripes, characterized by discontinuous jumps of the glassiness parameters. The glass physics of ultrasoft particles is hence richer than that of impenetrable particles for reasons that can be attributed to the ability of the former to create and break out-of-equilibrium clusters of overlapping particles.
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Affiliation(s)
- Jean-Marc Bomont
- Université de Lorraine, LCP-A2MC, UR 3469, 1 Blvd. François Arago, Metz F-57078, France
| | - Christos N Likos
- Faculty of Physics, University of Vienna, Boltzmanngasse 5, 1090 Vienna, Austria
| | - Jean-Pierre Hansen
- PHENIX, Sorbonne Université, F-75005 Paris, France
- Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, United Kingdom
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20
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Thermal Behaviour of Microgels Composed of Interpenetrating Polymer Networks of Poly( N-isopropylacrylamide) and Poly(acrylic acid): A Calorimetric Study. Polymers (Basel) 2021; 14:polym14010115. [PMID: 35012137 PMCID: PMC8747536 DOI: 10.3390/polym14010115] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 12/23/2021] [Accepted: 12/26/2021] [Indexed: 12/17/2022] Open
Abstract
Stimuli-responsive microgels have recently attracted great attention in fundamental research as their soft particles can be deformed and compressed at high packing fractions resulting in singular phase behaviours. Moreover, they are also well suited for a wide variety of applications such as drug delivery, tissue engineering, organ-on-chip devices, microlenses fabrication and cultural heritage. Here, thermoresponsive and pH-sensitive cross-linked microgels, composed of interpenetrating polymer networks of poly(N-isopropylacrylamide) (PNIPAM) and poly(acrylic acid) (PAAc), are synthesized by a precipitation polymerization method in water and investigated through differential scanning calorimetry in a temperature range across the volume phase transition temperature of PNIPAM microgels. The phase behaviour is studied as a function of heating/cooling rate, concentration, pH and PAAc content. At low concentrations and PAAc contents, the network interpenetration does not affect the transition temperature typical of PNIPAM microgel in agreement with previous studies; on the contrary, we show that it induces a marked decrease at higher concentrations. DSC analysis also reveals an increase of the overall calorimetric enthalpy with increasing concentration and a decrease with increasing PAAc content. These findings are discussed and explained as related to emerging aggregation processes that can be finely controlled by properly changing concentration, PAAc content an pH. A deep analysis of the thermodynamic parameters allows to draw a temperature–concentration state diagram in the investigated concentration range.
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21
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Dang S, Brady J, Rel R, Surineni S, O'Shaughnessy C, McGorty R. Core-shell droplets and microcapsules formed through liquid-liquid phase separation of a colloid-polymer mixture. SOFT MATTER 2021; 17:8300-8307. [PMID: 34550150 DOI: 10.1039/d1sm01091c] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Microcapsules allow for the controlled containment, transport, and release of cargoes ranging from pharmaceuticals to fragrances. Given the interest from a variety of industries in microcapsules and other core-shell structures, a multitude of fabrication strategies exist. Here, we report on a method relying on a mixture of temperature-responsive microgel particles, poly(N-isopropylacrylamide) (pNIPAM), and a polymer which undergo fluid-fluid phase separation. At room temperature this mixture separates into colloid-rich (liquid) and colloid-poor (gas) fluids. By heating the sample above a critical temperature where the microgel particles shrink dramatically and develop a more deeply attractive interparticle potential, the droplets of the colloid-rich phase become gel-like. As the temperature is lowered back to room temperature, these droplets of gelled colloidal particles reliquefy and phase separation within the droplet occurs. This phase separation leads to colloid-poor droplets within the colloid-rich droplets surrounded by a continuous colloid-poor phase. The gas/liquid/gas all-aqueous double emulsion lasts only a few minutes before a majority of the inner droplets escape. However, the colloid-rich shell of the core-shell droplets can solidify with the addition of salt. That this method creates core-shell structures with a shell composed of stimuli-sensitive microgel colloidal particles using only aqueous components makes it attractive for encapsulating biological materials and making capsules that respond to changes in, for example, temperature, salt concentration, or pH.
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Affiliation(s)
- Steven Dang
- Department of Physics and Biophysics, University of San Diego, San Diego, CA, 92110, USA.
| | - John Brady
- Department of Physics and Biophysics, University of San Diego, San Diego, CA, 92110, USA.
| | - Ryle Rel
- Department of Physics and Biophysics, University of San Diego, San Diego, CA, 92110, USA.
| | - Sreenidhi Surineni
- Department of Physics and Biophysics, University of San Diego, San Diego, CA, 92110, USA.
| | - Conor O'Shaughnessy
- Department of Physics and Biophysics, University of San Diego, San Diego, CA, 92110, USA.
| | - Ryan McGorty
- Department of Physics and Biophysics, University of San Diego, San Diego, CA, 92110, USA.
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22
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Two-step deswelling in the Volume Phase Transition of thermoresponsive microgels. Proc Natl Acad Sci U S A 2021; 118:2109560118. [PMID: 34508008 PMCID: PMC8449345 DOI: 10.1073/pnas.2109560118] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/04/2021] [Indexed: 11/18/2022] Open
Abstract
Microgels, colloidal-scale polymer networks, are the prototype soft colloids. When the constituent polymers are thermoresponsive, they undergo a volume phase transition (VPT) from a swollen to a collapsed state at a characteristic temperature, close to ambient one, of great appeal for several applications. To describe this phenomenon, microgels are usually treated as neutral, but here we show that electrostatics needs to be taken into account. In particular, deswelling occurs via a two-step, rather than a homogeneous, particle collapse, mainly driven by peripheral charges located on the microgel corona, for which we also establish a unifying framework encompassing all studied microgels. Our work thus provides a change of perspective to describe these fascinating systems. Thermoresponsive microgels are one of the most investigated types of soft colloids, thanks to their ability to undergo a Volume Phase Transition (VPT) close to ambient temperature. However, this fundamental phenomenon still lacks a detailed microscopic understanding, particularly regarding the presence and the role of charges in the deswelling process. This is particularly important for the widely used poly(N-isopropylacrylamide)–based microgels, where the constituent monomers are neutral but charged groups arise due to the initiator molecules used in the synthesis. Here, we address this point combining experiments with state-of-the-art simulations to show that the microgel collapse does not happen in a homogeneous fashion, but through a two-step mechanism, entirely attributable to electrostatic effects. The signature of this phenomenon is the emergence of a minimum in the ratio between gyration and hydrodynamic radii at the VPT. Thanks to simulations of microgels with different cross-linker concentrations, charge contents, and charge distributions, we provide evidence that peripheral charges arising from the synthesis are responsible for this behavior and we further build a universal master curve able to predict the two-step deswelling. Our results have direct relevance on fundamental soft condensed matter science and on applications where microgels are involved, ranging from materials to biomedical technologies.
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23
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Royall CP, Faers MA, Fussell SL, Hallett JE. Real space analysis of colloidal gels: triumphs, challenges and future directions. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:453002. [PMID: 34034239 DOI: 10.1088/1361-648x/ac04cb] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Accepted: 05/25/2021] [Indexed: 06/12/2023]
Abstract
Colloidal gels constitute an important class of materials found in many contexts and with a wide range of applications. Yet as matter far from equilibrium, gels exhibit a variety of time-dependent behaviours, which can be perplexing, such as an increase in strength prior to catastrophic failure. Remarkably, such complex phenomena are faithfully captured by an extremely simple model-'sticky spheres'. Here we review progress in our understanding of colloidal gels made through the use of real space analysis and particle resolved studies. We consider the challenges of obtaining a suitable experimental system where the refractive index and density of the colloidal particles is matched to that of the solvent. We review work to obtain a particle-level mechanism for rigidity in gels and the evolution of our understanding of time-dependent behaviour, from early-time aggregation to ageing, before considering the response of colloidal gels to deformation and then move on to more complex systems of anisotropic particles and mixtures. Finally we note some more exotic materials with similar properties.
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Affiliation(s)
- C Patrick Royall
- Gulliver UMR CNRS 7083, ESPCI Paris, Université PSL, 75005 Paris, France
- HH Wills Physics Laboratory, Tyndall Avenue, Bristol, BS8 1TL, United Kingdom
- School of Chemistry, University of Bristol, Cantock Close, Bristol, BS8 1TS, United Kingdom
- Centre for Nanoscience and Quantum Information, Tyndall Avenue, Bristol, BS8 1FD, United Kingdom
| | - Malcolm A Faers
- Bayer AG, Crop Science Division, Formulation Technology, Alfred Nobel Str. 50, 40789 Monheim, Germany
| | - Sian L Fussell
- School of Chemistry, University of Bristol, Cantock Close, Bristol, BS8 1TS, United Kingdom
- Bristol Centre for Functional Nanomaterials, University of Bristol, Tyndall Avenue, Bristol, BS8 1TL, United Kingdom
| | - James E Hallett
- Physical and Theoretical Chemistry Laboratory, South Parks Road, University of Oxford, OX1 3QZ, United Kingdom
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24
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Vialetto J, Camerin F, Grillo F, Ramakrishna SN, Rovigatti L, Zaccarelli E, Isa L. Effect of Internal Architecture on the Assembly of Soft Particles at Fluid Interfaces. ACS NANO 2021; 15:13105-13117. [PMID: 34328717 PMCID: PMC8388124 DOI: 10.1021/acsnano.1c02486] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Monolayers of soft colloidal particles confined at fluid interfaces are at the core of a broad range of technological processes, from the stabilization of responsive foams and emulsions to advanced lithographic techniques. However, establishing a fundamental relation between their internal architecture, which is controlled during synthesis, and their structural and mechanical properties upon interfacial confinement remains an elusive task. To address this open issue, which defines the monolayer's properties, we synthesize core-shell microgels, whose soft core can be chemically degraded in a controlled fashion. This strategy allows us to obtain a series of particles ranging from analogues of standard batch-synthesized microgels to completely hollow ones after total core removal. Combined experimental and numerical results show that our hollow particles have a thin and deformable shell, leading to a temperature-responsive collapse of the internal cavity and a complete flattening after adsorption at a fluid interface. Mechanical characterization shows that a critical degree of core removal is required to obtain soft disk-like particles at an oil-water interface, which present a distinct response to compression. At low packing fractions, the mechanical response of the monolayer is dominated by the outer polymer chains forming a corona surrounding the particles within the interfacial plane, regardless of the presence of a core. By contrast, at high compression, the absence of a core enables the particles to deform in the direction orthogonal to the interface and to be continuously compressed without altering the monolayer structure. These findings show how fine, single-particle architectural control during synthesis can be engineered to determine the interfacial behavior of microgels, enabling one to link particle conformation with the resulting material properties.
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Affiliation(s)
- Jacopo Vialetto
- Laboratory
for Soft Materials and Interfaces, Department of Materials, ETH Zürich, Vladimir-Prelog-Weg 5, 8093 Zürich, Switzerland
| | - Fabrizio Camerin
- CNR
Institute for Complex Systems, Uos Sapienza, P.le A. Moro 2, 00185 Roma, Italy
- Department
of Basic and Applied Sciences for Engineering, Sapienza University of Rome, via A. Scarpa 14, 00161 Roma, Italy
| | - Fabio Grillo
- Laboratory
for Soft Materials and Interfaces, Department of Materials, ETH Zürich, Vladimir-Prelog-Weg 5, 8093 Zürich, Switzerland
| | - Shivaprakash N. Ramakrishna
- Laboratory
for Soft Materials and Interfaces, Department of Materials, ETH Zürich, Vladimir-Prelog-Weg 5, 8093 Zürich, Switzerland
| | - Lorenzo Rovigatti
- CNR
Institute for Complex Systems, Uos Sapienza, P.le A. Moro 2, 00185 Roma, Italy
- Department
of Physics, Sapienza University of Rome, P.le A. Moro 2, 00185 Roma, Italy
| | - Emanuela Zaccarelli
- CNR
Institute for Complex Systems, Uos Sapienza, P.le A. Moro 2, 00185 Roma, Italy
- Department
of Physics, Sapienza University of Rome, P.le A. Moro 2, 00185 Roma, Italy
| | - Lucio Isa
- Laboratory
for Soft Materials and Interfaces, Department of Materials, ETH Zürich, Vladimir-Prelog-Weg 5, 8093 Zürich, Switzerland
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25
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Frenzel L, Dartsch M, Balaguer GM, Westermeier F, Grübel G, Lehmkühler F. Glass-liquid and glass-gel transitions of soft-shell particles. Phys Rev E 2021; 104:L012602. [PMID: 34412357 DOI: 10.1103/physreve.104.l012602] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Accepted: 06/23/2021] [Indexed: 12/12/2022]
Abstract
We study the structure and dynamics of colloidal particles with a spherical hard core and a thermo-responsive soft shell over the whole phase diagram by means of small-angle x-ray scattering and x-ray photon correlation spectroscopy. By changing the effective volume fraction by temperature and particle concentration, liquid, repulsive glass. and attractive gel phases are observed. The dynamics slow down with increasing volume fraction in the liquid phase and reflect a Vogel-Fulcher-Tamann behavior known for fragile glass formers. We find a liquid-glass transition above 50 vol.% that is independent of the particles' concentration and temperature. In an overpacked state at effective volume fractions above 1, the dispersion does not show a liquid phase but undergoes a gel-glass transition at an effective volume fraction of 34 vol.%. At the same concentration, extrema of subdiffusive dynamics are found in the liquid phase at lower weight fractions. We interpret this as dynamic precursors of the glass-gel transition.
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Affiliation(s)
- Lara Frenzel
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany.,The Hamburg Centre for Ultrafast Imaging, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Michael Dartsch
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany.,The Hamburg Centre for Ultrafast Imaging, Luruper Chaussee 149, 22761 Hamburg, Germany
| | | | - Fabian Westermeier
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany
| | - Gerhard Grübel
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany.,The Hamburg Centre for Ultrafast Imaging, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Felix Lehmkühler
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany.,The Hamburg Centre for Ultrafast Imaging, Luruper Chaussee 149, 22761 Hamburg, Germany
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26
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From Femtoseconds to Hours—Measuring Dynamics over 18 Orders of Magnitude with Coherent X-rays. APPLIED SCIENCES-BASEL 2021. [DOI: 10.3390/app11136179] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
X-ray photon correlation spectroscopy (XPCS) enables the study of sample dynamics between micrometer and atomic length scales. As a coherent scattering technique, it benefits from the increased brilliance of the next-generation synchrotron radiation and Free-Electron Laser (FEL) sources. In this article, we will introduce the XPCS concepts and review the latest developments of XPCS with special attention on the extension of accessible time scales to sub-μs and the application of XPCS at FELs. Furthermore, we will discuss future opportunities of XPCS and the related technique X-ray speckle visibility spectroscopy (XSVS) at new X-ray sources. Due to its particular signal-to-noise ratio, the time scales accessible by XPCS scale with the square of the coherent flux, allowing to dramatically extend its applications. This will soon enable studies over more than 18 orders of magnitude in time by XPCS and XSVS.
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27
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Immink JN, Bergman MJ, Maris JJE, Stenhammar J, Schurtenberger P. Crystal-to-Crystal Transitions in Binary Mixtures of Soft Colloids. ACS NANO 2020; 14:14861-14868. [PMID: 33191738 PMCID: PMC7690049 DOI: 10.1021/acsnano.0c03966] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 11/11/2020] [Indexed: 05/31/2023]
Abstract
In this article, we demonstrate a method for inducing reversible crystal-to-crystal transitions in binary mixtures of soft colloidal particles. Through a controlled decrease of salinity and increasingly dominating electrostatic interactions, a single sample is shown to reversibly organize into entropic crystals, electrostatic attraction-dominated crystals, or aggregated gels, which we quantify using microscopy and image analysis. We furthermore analyze crystalline structures with bond order analysis to discern between two crystal phases. We observe the different phases using a sample holder geometry that allows both in situ salinity control and imaging through confocal laser scanning microscopy and apply a synthesis method producing particles with high resolvability in microscopy with control over particle size. The particle softness provides for an enhanced crystallization speed, while altering the re-entrant melting behavior as compared to hard sphere systems. This work thus provides several tools for use in the reproducible manufacture and analysis of binary colloidal crystals.
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Affiliation(s)
- Jasper N. Immink
- Division
of Physical Chemistry, Lund University, 221 00 Lund, Sweden
| | - Maxime J. Bergman
- Department
of Physics, University of Fribourg, 1700 Fribourg, Switzerland
| | - J. J. Erik Maris
- Inorganic
Chemistry and Catalysis Group, Utrecht University, 3584 CS Utrecht, The Netherlands
| | - Joakim Stenhammar
- Division
of Physical Chemistry, Lund University, 221 00 Lund, Sweden
| | - Peter Schurtenberger
- Division
of Physical Chemistry, Lund University, 221 00 Lund, Sweden
- Lund
Institute of advanced Neutron and X-ray Science (LINXS), Lund University, 221 00 Lund, Sweden
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28
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Farnaz Fazlalizadeh, Massoumi B, Banaei A, Jaymand M. A Thermal-Responsive Y-Shaped Miktoarm Amphiphilic Block Copolymer Composed of Poly(ε-caprolactone) and Poly(N-isopropylacrylamide) as a Nano-micellar Carrier for Anti-cancer Drugs. POLYMER SCIENCE SERIES B 2020. [DOI: 10.1134/s1560090420050061] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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29
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Abstract
Grain growth under shear annealing is crucial for controlling the properties of polycrystalline materials. However, their microscopic kinetics are not well understood because individual atomic trajectories are difficult to track. Here, we study grain growth with single-particle kinetics in colloidal polycrystals using video microscopy. Rich grain-growth phenomena are revealed in three shear regimes, including the normal grain growth (NGG) in weak shear melting-recrystallization process in strong shear. For intermediate shear, early stage NGG is arrested by built-up stress and eventually gives way to dynamic abnormal grain growth (DAGG). We find that DAGG occurs via a melting-recrystallization process, which naturally explains the puzzling stress drop at the onset of DAGG in metals. Moreover, we visualize that grain boundary (GB) migration is coupled with shear via disconnection gliding. The disconnection-gliding dynamics and the collective motions of ambient particles are resolved. We also observed that grain rotation can violate the conventional relation [Formula: see text] (R is the grain radius, and θ is the misorientation angle between two grains) by emission and annihilation of dislocations across the grain, resulting in a step-by-step rotation. Besides grain growth, we discover a result in shear-induced melting: The melting volume fraction varies sinusoidally on the angle mismatch between the triangular lattice orientation of the grain and the shear direction. These discoveries hold potential to inform microstructure engineering of polycrystalline materials.
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30
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Scheffold F. Pathways and challenges towards a complete characterization of microgels. Nat Commun 2020; 11:4315. [PMID: 32887886 PMCID: PMC7473851 DOI: 10.1038/s41467-020-17774-5] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2019] [Accepted: 07/20/2020] [Indexed: 01/07/2023] Open
Abstract
Due to their controlled size, sensitivity to external stimuli, and ease-of-use, microgel colloids are unique building blocks for soft materials made by crosslinking polymers on the micrometer scale. Despite the plethora of work published, many questions about their internal structure, interactions, and phase behavior are still open. The reasons for this lack of understanding are the challenges arising from the small size of the microgel particles, complex pairwise interactions, and their solvent permeability. Here we describe pathways toward a complete understanding of microgel colloids based on recent experimental advances in nanoscale characterization, such as super-resolution microscopy, scattering methods, and modeling.
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Affiliation(s)
- Frank Scheffold
- Department of Physics, University of Fribourg, Chemin du Musée 3, 1700, Fribourg, Switzerland.
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31
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Minato H, Nishizawa Y, Uchihashi T, Suzuki D. Thermoresponsive structural changes of single poly(N-isopropyl acrylamide) hydrogel microspheres under densely packed conditions on a solid substrate. Polym J 2020. [DOI: 10.1038/s41428-020-0372-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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32
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Minami S, Watanabe T, Sasaki Y, Minato H, Yamamoto A, Suzuki D, Urayama K. Two-step yielding behavior of densely packed microgel mixtures with chemically dissimilar surfaces and largely different sizes. SOFT MATTER 2020; 16:7400-7413. [PMID: 32699868 DOI: 10.1039/d0sm00366b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Steady-state flow and elastic behavior is investigated for the moderately concentrated binary suspensions of soft microgels (pastes) with chemically dissimilar surfaces, and various degrees of size- and stiffness disparities. The pastes of poly(N-isopropyl acrylamide) (N) and poly(N-isopropyl methacrylamide) (NM) microgels with different values of yield strain γc (γNc > γNMc) are employed as the components. For the single microgel pastes (φ ≈ 1 where φ is apparent volume fraction), the values of γc are governed by the chemical species of constituent polymer in microgel surface whereas γc is insensitive to cross-link density and particle size. We demonstrate that the binary N/NM pastes with large size disparity (RN/NM = DN/DNM < 0.26 where D is the microgel diameter) at low φN (φN: weight fraction of small N microgels) exhibit the peculiarities in several rheological aspects, i.e., the two-step yielding in steady-state flow, and their values of γc and equilibrium shear modulus (G0) being equivalent to those of the single large NM microgel paste. These peculiarities are attributed to the characteristic packing resulting from large size disparity in which all or almost of the small N microgels tend to be accommodated in the gap between the large NM microgels even in moderately concentrated state. This characteristic packing substantially masks the contribution of the small N microgels at low φN, explaining the φN-independent G0 and γc as well as the first yielding governed solely by the large NM microgels. The second yielding results from the emerged contribution of the small N microgels expelled out from the gap by the positional rearrangements after the first yielding. The binary homo-N/N pastes with the similarly large size disparity at low φsmall also exhibit the φsmall-independent values of G0, but they show one-step yielding, indicating that the two-step yielding requires not only sufficiently large size disparity but also chemical dissimilarity (different values of γc) between the two components.
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Affiliation(s)
- Saori Minami
- Department of Macromolecular Science and Engineering, Kyoto Institute of Technology, Sakyo-ku, Kyoto 606-8585, Japan.
| | - Takumi Watanabe
- Graduate School of Textile Science & Technology, Shinshu University, Ueda 386-8567, Japan.
| | - Yuma Sasaki
- Graduate School of Textile Science & Technology, Shinshu University, Ueda 386-8567, Japan.
| | - Haruka Minato
- Graduate School of Textile Science & Technology, Shinshu University, Ueda 386-8567, Japan.
| | - Atsushi Yamamoto
- Department of Macromolecular Science and Engineering, Kyoto Institute of Technology, Sakyo-ku, Kyoto 606-8585, Japan.
| | - Daisuke Suzuki
- Graduate School of Textile Science & Technology, Shinshu University, Ueda 386-8567, Japan. and Research Initiative for Supra-Materials, Interdisciplinary Cluster for Cutting Edge Research, Shinshu University, Ueda 386-8567, Japan
| | - Kenji Urayama
- Department of Macromolecular Science and Engineering, Kyoto Institute of Technology, Sakyo-ku, Kyoto 606-8585, Japan.
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33
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Di Napoli B, Franco S, Severini L, Tumiati M, Buratti E, Titubante M, Nigro V, Gnan N, Micheli L, Ruzicka B, Mazzuca C, Angelini R, Missori M, Zaccarelli E. Gellan Gum Microgels as Effective Agents for a Rapid Cleaning of Paper. ACS APPLIED POLYMER MATERIALS 2020; 2:2791-2801. [PMID: 32685926 PMCID: PMC7359273 DOI: 10.1021/acsapm.0c00342] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Accepted: 05/27/2020] [Indexed: 05/21/2023]
Abstract
Microgel particles have emerged in the past few years as a favorite model system for fundamental science and for innovative applications ranging from the industrial to biomedical fields. Despite their potentialities, no works so far have focused on the application of microgels for cultural heritage preservation. Here we show their first use for this purpose, focusing on wet paper cleaning. Exploiting their retentive properties, microgels are able to clean paper, ensuring more controlled water release from the gel matrix, in analogy to their macroscopic counterpart, i.e., hydrogels. However, differently from these, the reduced size of microgels makes them suitable to efficiently penetrate in the porous structure of the paper and to easily adapt to the irregular surfaces of the artifacts. To test their cleaning abilities, we prepare microgels made of Gellan gum, a natural and widespread material already used as a hydrogel for paper cleaning, and apply them to modern and ancient paper samples. Combining several diagnostic methods, we show that microgels performances in the removal of cellulose degradation byproducts for ancient samples are superior to commonly employed hydrogels and water bath treatments. This is due to the composition and morphology of ancient paper, which facilitates microgels penetration. For modern paper cleaning, performances are at least comparable to the other methods. In all cases, the application of microgels takes place on a time scale of a few minutes, opening the way for widespread use as a rapid and efficient cleaning protocol.
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Affiliation(s)
- Benedetta Di Napoli
- Institute
for Complex Systems, National Research Council (CNR-ISC) and Department
of Physics, Sapienza University of Rome, Piazzale A. Moro 2, 00185 Rome, Italy
- Department
of Chemical Sciences and Technologies, University
of Rome Tor Vergata, Via della Ricerca Scientifica I, 00133 Rome, Italy
| | - Silvia Franco
- Institute
for Complex Systems, National Research Council (CNR-ISC) and Department
of Physics, Sapienza University of Rome, Piazzale A. Moro 2, 00185 Rome, Italy
| | - Leonardo Severini
- Department
of Chemical Sciences and Technologies, University
of Rome Tor Vergata, Via della Ricerca Scientifica I, 00133 Rome, Italy
| | - Manuel Tumiati
- Department
of Chemical Sciences and Technologies, University
of Rome Tor Vergata, Via della Ricerca Scientifica I, 00133 Rome, Italy
| | - Elena Buratti
- Institute
for Complex Systems, National Research Council (CNR-ISC) and Department
of Physics, Sapienza University of Rome, Piazzale A. Moro 2, 00185 Rome, Italy
| | - Mattia Titubante
- Department
of Chemical Sciences and Technologies, University
of Rome Tor Vergata, Via della Ricerca Scientifica I, 00133 Rome, Italy
| | - Valentina Nigro
- Institute
for Complex Systems, National Research Council (CNR-ISC) and Department
of Physics, Sapienza University of Rome, Piazzale A. Moro 2, 00185 Rome, Italy
- ENEA
C.R. Frascati, FSN-TECFIS-MNF
Photonics Micro and Nanostructures Laboratory, Via E. Fermi 45, 00044 Frascati, Roma, Italy
| | - Nicoletta Gnan
- Institute
for Complex Systems, National Research Council (CNR-ISC) and Department
of Physics, Sapienza University of Rome, Piazzale A. Moro 2, 00185 Rome, Italy
| | - Laura Micheli
- Department
of Chemical Sciences and Technologies, University
of Rome Tor Vergata, Via della Ricerca Scientifica I, 00133 Rome, Italy
| | - Barbara Ruzicka
- Institute
for Complex Systems, National Research Council (CNR-ISC) and Department
of Physics, Sapienza University of Rome, Piazzale A. Moro 2, 00185 Rome, Italy
| | - Claudia Mazzuca
- Department
of Chemical Sciences and Technologies, University
of Rome Tor Vergata, Via della Ricerca Scientifica I, 00133 Rome, Italy
| | - Roberta Angelini
- Institute
for Complex Systems, National Research Council (CNR-ISC) and Department
of Physics, Sapienza University of Rome, Piazzale A. Moro 2, 00185 Rome, Italy
| | - Mauro Missori
- Institute
for Complex Systems, National Research Council (CNR-ISC) and Department
of Physics, Sapienza University of Rome, Piazzale A. Moro 2, 00185 Rome, Italy
| | - Emanuela Zaccarelli
- Institute
for Complex Systems, National Research Council (CNR-ISC) and Department
of Physics, Sapienza University of Rome, Piazzale A. Moro 2, 00185 Rome, Italy
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34
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Frenzel L, Lokteva I, Koof M, Narayanan S, Grübel G, Lehmkühler F. Influence of TMAO as co-solvent on the gelation of silica-PNIPAm core-shell nanogels at intermediate volume fractions. Chemphyschem 2020; 21:1318-1325. [PMID: 32250508 PMCID: PMC7318175 DOI: 10.1002/cphc.202000114] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 03/20/2020] [Indexed: 12/29/2022]
Abstract
We study the structure and dynamics of poly(N-isopropylacrylamide) (PNIPAm) core-shell nanogels dispersed in aqueous trimethylamine N-oxide (TMAO) solutions by means of small-angle X-ray scattering and X-ray photon correlation spectroscopy (XPCS). Upon increasing the temperature above the lower critical solution temperature of PNIPAm at 33 °C, a colloidal gel is formed as identified by an increase of I(q) at small q as well as a slowing down of sample dynamics by various orders of magnitude. With increasing TMAO concentration the gelation transition shifts linearly to lower temperatures. Above a TMAO concentration of approximately 0.40 mol/L corresponding to a 1 : 1 ratio of TMAO and NIPAm groups, collapsed PNIPAm states are found for all temperatures without any gelation transition. This suggests that reduction of PNIPAm-water hydrogen bonds due to the presence of TMAO results in a stabilisation of the collapsed PNIPAm state and suppresses gelation of the nanogel.
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Affiliation(s)
- Lara Frenzel
- Deutsches Elektronen-Synchrotron DESYNotkestr. 8522607HamburgGermany
- The Hamburg Centre for Ultrafast ImagingLuruper Chaussee 14922761HamburgGermany
| | - Irina Lokteva
- Deutsches Elektronen-Synchrotron DESYNotkestr. 8522607HamburgGermany
- The Hamburg Centre for Ultrafast ImagingLuruper Chaussee 14922761HamburgGermany
| | - Michael Koof
- Deutsches Elektronen-Synchrotron DESYNotkestr. 8522607HamburgGermany
- The Hamburg Centre for Ultrafast ImagingLuruper Chaussee 14922761HamburgGermany
| | - Suresh Narayanan
- Advanced Photon SourceArgonne National LaboratoryArgonneIllinois60439United States
| | - Gerhard Grübel
- Deutsches Elektronen-Synchrotron DESYNotkestr. 8522607HamburgGermany
- The Hamburg Centre for Ultrafast ImagingLuruper Chaussee 14922761HamburgGermany
| | - Felix Lehmkühler
- Deutsches Elektronen-Synchrotron DESYNotkestr. 8522607HamburgGermany
- The Hamburg Centre for Ultrafast ImagingLuruper Chaussee 14922761HamburgGermany
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35
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Arismendi-Arrieta DJ, Moreno AJ. Deformability and solvent penetration in soft nanoparticles at liquid-liquid interfaces. J Colloid Interface Sci 2020; 570:212-222. [DOI: 10.1016/j.jcis.2020.02.102] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 02/24/2020] [Accepted: 02/25/2020] [Indexed: 12/29/2022]
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36
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Zanatta M, Tavagnacco L, Buratti E, Chiessi E, Natali F, Bertoldo M, Orecchini A, Zaccarelli E. Atomic scale investigation of the volume phase transition in concentrated PNIPAM microgels. J Chem Phys 2020; 152:204904. [PMID: 32486676 DOI: 10.1063/5.0007112] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Combining elastic incoherent neutron scattering and differential scanning calorimetry, we investigate the occurrence of the volume phase transition (VPT) in very concentrated poly-(N-isopropyl-acrylamide) (PNIPAM) microgel suspensions, from a polymer weight fraction of 30 wt. % up to dry conditions. Although samples are arrested at the macroscopic scale, atomic degrees of freedom are equilibrated and can be probed in a reproducible way. A clear signature of the VPT is present as a sharp drop in the mean square displacement of PNIPAM hydrogen atoms obtained by neutron scattering. As a function of concentration, the VPT gets smoother as dry conditions are approached, whereas the VPT temperature shows a minimum at about 43 wt. %. This behavior is qualitatively confirmed by calorimetry measurements. Molecular dynamics simulations are employed to complement experimental results and gain further insights into the nature of the VPT, confirming that it involves the formation of an attractive gel state between the microgels. Overall, these results provide evidence that the VPT in PNIPAM-based systems can be detected at different time- and length-scales as well as under overcrowded conditions.
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Affiliation(s)
- M Zanatta
- Department of Physics, University of Trento, I-38123 Trento, Italy
| | - L Tavagnacco
- CNR-ISC and Department of Physics, Sapienza University of Rome, I-00185 Roma, Italy
| | - E Buratti
- CNR-ISC and Department of Physics, Sapienza University of Rome, I-00185 Roma, Italy
| | - E Chiessi
- Department of Chemical Sciences and Technologies, University of Rome Tor Vergata, I-00133 Roma, Italy
| | - F Natali
- CNR-IOM, Operative Group in Grenoble (OGG), c/o Institut Laue Langevin, F-38042 Grenoble, France
| | - M Bertoldo
- Department of Chemical and Pharmaceutical Sciences, University of Ferrara, I-44121 Ferrara, Italy
| | - A Orecchini
- Department of Physics and Geology, University of Perugia, I-06123 Perugia, Italy
| | - E Zaccarelli
- CNR-ISC and Department of Physics, Sapienza University of Rome, I-00185 Roma, Italy
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37
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Bergman MJ, Pedersen JS, Schurtenberger P, Boon N. Controlling the morphology of microgels by ionic stimuli. SOFT MATTER 2020; 16:2786-2794. [PMID: 32104825 DOI: 10.1039/c9sm02170a] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Stimuli-responsive microgels have attracted much interest for their use as vehicles for drug delivery or as the building blocks of adaptive materials. Ionic microgel particles, including popular poly(NIPAM-co-acrylic acid), show strong mechanical responsiveness to many external stimuli, including changes in ionic strength or acidity. In this work, we demonstrate that combining multiple ionic stimuli can enable detailed control over the morphology of microgels. To this extent, we analyze the particle morphology in various surroundings with light-scattering techniques. First, we find strong indications of an inverted density profile in the core of the particles. Secondly, we show that the swelling of this hydrogel core and the corona of dangling polymer ends can be targeted separately by a combination of deionization and deprotonation steps. Hence, this work represents an advance in tailoring particle morphologies after synthesis in a predictable fashion.
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Affiliation(s)
- Maxime J Bergman
- Division of Physical Chemistry, Lund University, SE-22100 Lund, Sweden.
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38
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Månsson LK, Peng F, Crassous JJ, Schurtenberger P. A microgel-Pickering emulsion route to colloidal molecules with temperature-tunable interaction sites. SOFT MATTER 2020; 16:1908-1921. [PMID: 31995090 DOI: 10.1039/c9sm02401h] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
A simple Pickering emulsion route has been developed for the assembly of temperature-responsive poly(N-isopropylacrylamide) (PNIPAM) microgel particles into colloidal molecules comprising a small number of discrete microgel interaction sites on a central oil emulsion droplet. Here, the surface activity of the microgels serves to drive their assembly through adsorption to growing polydimethylsiloxane (PDMS) emulsion oil droplets of high monodispersity, prepared in situ via ammonia-catalysed hydrolysis and condensation of dimethyldiethoxysilane (DMDES). A dialysis step is employed in order to limit further growth once the target assembly size has been reached, thus yielding narrowly size-distributed, colloidal molecule-like microgel-Pickering emulsion oil droplets with well-defined microgel interaction sites. The temperature-responsiveness of the PNIPAM interaction sites will allow for the directional interactions to be tuned in a facile manner with temperature, all the way from soft repulsive to short-range attractive as the their volume phase transition temperature (VPTT) is crossed. Finally, the microgel-Pickering emulsion approach is extended to a mixture of PNIPAM and poly(N-isopropylmethacrylamide) (PNIPMAM) microgels that differ with respect to their VPTT, this in order to prepare patchy colloidal molecules where the directional interactions will be more readily resolved.
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Affiliation(s)
- Linda K Månsson
- Division of Physical Chemistry, Lund University, POB 124, SE-22100 Lund, Sweden. and NanoLund, POB 118, SE-22100 Lund, Sweden
| | - Feifei Peng
- Division of Physical Chemistry, Lund University, POB 124, SE-22100 Lund, Sweden. and NanoLund, POB 118, SE-22100 Lund, Sweden
| | - Jérôme J Crassous
- Institute of Physical Chemistry, RWTH Aachen University, 52074 AAchen, Germany
| | - Peter Schurtenberger
- Division of Physical Chemistry, Lund University, POB 124, SE-22100 Lund, Sweden. and NanoLund, POB 118, SE-22100 Lund, Sweden and Lund Institute of Advanced Neutron and X-ray Science (LINXS), Scheelevägen 19, SE-22370 Lund, Sweden
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39
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Frenzel L, Lehmkühler F, Koof M, Lokteva I, Grübel G. The phase diagram of colloidal silica-PNIPAm core-shell nanogels. SOFT MATTER 2020; 16:466-475. [PMID: 31803889 DOI: 10.1039/c9sm01884k] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
We study the structure and dynamics of aqueous dispersions of densely packed core-shell nanoparticles composed of a silica core and a poly(N-isoproylacrylamide) (PNIPAm) shell as a function of temperature and concentration. With small angle X-ray scattering (SAXS) and X-ray photon correlation spectroscopy (XPCS) we shed light on the structural and dynamical changes of the thermo-responsive colloidal nanogel during its volume phase transition at a lower critical solution temperature (LCST) of 32 °C. A transition of the dynamics and its distinct dependency on the particle number concentration could be determined by analysing the intensity autocorrelation function while the structural transition remains concentration independent. We found the dynamics of a jammed system beyond a critical concentration. In addition, by variation of the PNIPAm shell size we tuned both the effective volume fraction and the underlying nature of the dynamics in the system. With our results we can present a full phase diagram of a PNIPAm core-shell system that spans from diluted suspensions, where the system behaves like a liquid, to an effective volume fraction of more than ninety percent where after exceeding a critical concentration the system undergoes a temperature-induced transition from a liquid towards a colloidal gel.
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Affiliation(s)
- Lara Frenzel
- Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, 22607 Hamburg, Germany.
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40
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Schmitt J, Hartwig C, Crassous JJ, Mihut AM, Schurtenberger P, Alfredsson V. Anisotropic mesoporous silica/microgel core–shell responsive particles. RSC Adv 2020; 10:25393-25401. [PMID: 35517484 PMCID: PMC9055282 DOI: 10.1039/d0ra02278k] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Accepted: 06/24/2020] [Indexed: 12/14/2022] Open
Abstract
Hybrid anisotropic microgels were synthesised using mesoporous silica as core particles. By finely controlling the synthesis conditions, the latter can be obtained with different shapes such as platelets, primary particles or rods. Using the core particles as seeds for precipitation polymerisation, a crosslinked poly(N-isopropylacrylamide) (PNIPAM) microgel shell could be grown at the surface, conferring additional thermo-responsive properties. The different particles were characterised using scattering and imaging techniques. Small angle X-ray scattering (SAXS) was employed to identify the shape and porous organisation of the core particles and dynamic light scattering (DLS) to determine the swelling behaviour of the hybrid microgels. In addition, cryogenic transmission electron microscopy (cryo-TEM) imaging of the hybrids confirms the different morphologies as well as the presence of the microgel network and the core–shell conformation. Finally, the response of the particles to an alternating electric field is demonstrated for hybrid rod-shaped microgels in situ using confocal laser scanning microscopy (CLSM). Hybrid anisotropic microgels with different morphologies were prepared using mesoporous silica particles as core and PNIPAM as shell. The shell thickness d and aspect ratio ρ were characterised notably via cryo-TEM (left) and DLS (right).![]()
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Affiliation(s)
- Julien Schmitt
- Division of Physical Chemistry
- Department of Chemistry
- Lund University
- 221 00 Lund
- Sweden
| | - Caroline Hartwig
- Division of Physical Chemistry
- Department of Chemistry
- Lund University
- 221 00 Lund
- Sweden
| | - Jérôme J. Crassous
- Division of Physical Chemistry
- Department of Chemistry
- Lund University
- 221 00 Lund
- Sweden
| | - Adriana M. Mihut
- Division of Physical Chemistry
- Department of Chemistry
- Lund University
- 221 00 Lund
- Sweden
| | - Peter Schurtenberger
- Division of Physical Chemistry
- Department of Chemistry
- Lund University
- 221 00 Lund
- Sweden
| | - Viveka Alfredsson
- Division of Physical Chemistry
- Department of Chemistry
- Lund University
- 221 00 Lund
- Sweden
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41
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Tong H, Tanaka H. Structural order as a genuine control parameter of dynamics in simple glass formers. Nat Commun 2019; 10:5596. [PMID: 31811143 PMCID: PMC6898187 DOI: 10.1038/s41467-019-13606-3] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Accepted: 11/13/2019] [Indexed: 11/13/2022] Open
Abstract
Glass transition is characterised by drastic dynamical slowing down upon cooling, accompanied by growing spatial heterogeneity. Its rationalisation by subtle changes in the liquid structure has been long debated but remains elusive, due to intrinsic difficulty in detecting the underlying complex structural ordering. Here we report that structural order parameter characterising local packing capability can well describe the glassy dynamics not only macroscopically but also microscopically, no matter whether it is driven by temperature or density. A Vogel-Fulcher-Tammann (VFT)-like relation is universally identified between the structural relaxation time and the order parameter for supercooled liquids with isotropic interactions. More importantly, we find such an intriguing VFT-like relation to be statistically valid even at a particle level, between spatially coarse-grained structural order and microscopic particle-level dynamics. Such a unified description of glassy dynamics based solely on structural order is expected to contribute to the ultimate understanding of the long-standing glass-transition problem. The glass-forming materials exhibit dynamical slowing down together with spatial heterogeneity at microscales, but their origin remains debated. Tong and Tanaka show that this phenomenon can be unified based on a structural order parameter capable of detecting subtle ordering in instantaneous liquid states.
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Affiliation(s)
- Hua Tong
- Department of Fundamental Engineering, Institute of Industrial Science, University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo, 153-8505, Japan
| | - Hajime Tanaka
- Department of Fundamental Engineering, Institute of Industrial Science, University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo, 153-8505, Japan.
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42
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Otanicar T, Patel J, Sarica E. Mechanical milling of thermoresponsive poly(
N
‐isopropylacrylamide) hydrogel for particle‐oriented oil–water separation. J Appl Polym Sci 2019. [DOI: 10.1002/app.48771] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- Todd Otanicar
- Department of Mechanical EngineeringUniversity of Tulsa Tulsa Oklahoma 74104
- Department of Mechanical and Biomedical EngineeringBoise State University Boise Idaho 83725
| | - Jay Patel
- Department of Mechanical EngineeringUniversity of Tulsa Tulsa Oklahoma 74104
| | - Erhan Sarica
- Department of Mechanical EngineeringUniversity of Tulsa Tulsa Oklahoma 74104
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43
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Nickel AC, Scotti A, Houston JE, Ito T, Crassous J, Pedersen JS, Richtering W. Anisotropic Hollow Microgels That Can Adapt Their Size, Shape, and Softness. NANO LETTERS 2019; 19:8161-8170. [PMID: 31613114 DOI: 10.1021/acs.nanolett.9b03507] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
The development of soft anisotropic building blocks is of great interest for various applications in soft matter. Furthermore, such systems would be important model systems for ordering phenomena in fundamental soft matter science. In this work, we address the challenge of creating hollow and anisotropically shaped thermoresponsive microgels, polymeric networks with a solvent filled cavity in their center that are swollen in a good solvent. Sacrificial elliptical hematite silica particles were utilized as a template for the synthesis of a cross-linked N-isopropylacrylamide (NIPAm) shell. By varying the amount of NIPAm, two anisotropic microgels were synthesized with either a thin or thick microgel shell. We characterized these precursor core-shell and the resulting hollow microgels using a combination of light, X-ray, and neutron scattering. New form factor models, accounting for the cavity, the polymer distribution and the anisotropy, have been developed for fitting the scattering data. With such models, we demonstrated the existence of the cavity and simultaneously the anisotropic character of the microgels. Furthermore, we show that the thickness of the shell has a major influence on the shape and the cavity dimension of the microgel after etching of the sacrificial core. Finally, the effect of temperature is investigated, showing that changes in size, softness, and aspect ratio are triggered by temperature.
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Affiliation(s)
- Anne C Nickel
- Institute of Physical Chemistry , RWTH Aachen University , 52056 Aachen , Germany
| | - Andrea Scotti
- Institute of Physical Chemistry , RWTH Aachen University , 52056 Aachen , Germany
| | - Judith E Houston
- Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ) , Forschungszentrum Jülich GmbH , Lichtenbergstrasse 1 , 85748 Garching , Germany
- European Spallation Source ERIC , Box 176, SE-221 00 Lund , Sweden
| | - Thiago Ito
- Physical Chemistry, Department of Chemistry , Lund University , SE-221 00 Lund , Sweden
| | - Jérôme Crassous
- Institute of Physical Chemistry , RWTH Aachen University , 52056 Aachen , Germany
| | - Jan Skov Pedersen
- Department of Chemistry and Interdisciplinary Nanoscience Centre (iNANO) , University of Aarhus , Gustav Wieds Vej 14 , DK-8000 Aarhus C , Denmark
| | - Walter Richtering
- Institute of Physical Chemistry , RWTH Aachen University , 52056 Aachen , Germany
- JARA-SOFT , 52056 Aachen , Germany
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Månsson LK, de Wild T, Peng F, Holm SH, Tegenfeldt JO, Schurtenberger P. Preparation of colloidal molecules with temperature-tunable interactions from oppositely charged microgel spheres. SOFT MATTER 2019; 15:8512-8524. [PMID: 31633148 DOI: 10.1039/c9sm01779h] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The self-assembly of small colloidal clusters, so-called colloidal molecules, into crystalline materials has proven extremely challenging, the outcome often being glassy, amorphous states where positions and orientations are locked. In this paper, a new type of colloidal molecule is therefore prepared, assembled from poly(N-isopropylacrylamide) (PNIPAM)-based microgels that due to their well documented softness and temperature-response allow for greater defect tolerance compared to hard spheres and for convenient in situ tuning of size, volume fraction and inter-particle interactions with temperature. The microgels (B) are assembled by electrostatic adsorption onto oppositely charged, smaller-sized microgels (A), where the relative size of the two determines the valency (n) of the resulting core-satellite ABn-type colloidal molecules. Following assembly, a microfluidic deterministic lateral displacement (DLD) device is used to effectively isolate AB4-type colloidal molecules of tetrahedral geometry that possess a repulsive-to-attractive transition on crossing the microgels' volume phase transition temperature (VPTT). These soft, temperature-responsive colloidal molecules constitute highly promising building blocks for the preparation of new materials with emergent properties, and their optical wavelength-size makes them especially interesting for optical applications.
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Affiliation(s)
- Linda K Månsson
- Division of Physical Chemistry, Lund University, POB 124, SE-22100 Lund, Sweden. and NanoLund, POB 118, SE-22100 Lund, Sweden
| | - Tym de Wild
- Division of Physical Chemistry, Lund University, POB 124, SE-22100 Lund, Sweden.
| | - Feifei Peng
- Division of Physical Chemistry, Lund University, POB 124, SE-22100 Lund, Sweden. and NanoLund, POB 118, SE-22100 Lund, Sweden
| | - Stefan H Holm
- NanoLund, POB 118, SE-22100 Lund, Sweden and Division of Solid State Physics, Lund University, POB 118, SE-22100 Lund, Sweden
| | - Jonas O Tegenfeldt
- NanoLund, POB 118, SE-22100 Lund, Sweden and Division of Solid State Physics, Lund University, POB 118, SE-22100 Lund, Sweden
| | - Peter Schurtenberger
- Division of Physical Chemistry, Lund University, POB 124, SE-22100 Lund, Sweden. and NanoLund, POB 118, SE-22100 Lund, Sweden and Lund Institute of Advanced Neutron and X-ray Science (LINXS), Scheelevägen 19, SE-22370 Lund, Sweden
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45
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Del Monte G, Ninarello A, Camerin F, Rovigatti L, Gnan N, Zaccarelli E. Numerical insights on ionic microgels: structure and swelling behaviour. SOFT MATTER 2019; 15:8113-8128. [PMID: 31589214 DOI: 10.1039/c9sm01253b] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Recent progress has been made in the numerical modelling of neutral microgel particles with a realistic, disordered structure. In this work we extend this approach to the case of co-polymerised microgels where a thermoresponsive polymer is mixed with acidic groups. We compare the cases where counterions directly interact with microgel charges or are modelled implicitly through a Debye-Hückel description. We do so by performing extensive numerical simulations of single microgels across the volume phase transition (VPT) varying the temperature and the fraction of charged monomers. We find that the presence of charges considerably alters the microgel structure, quantified by the monomer density profiles and by the form factors of the microgels, particularly close to the VPT. We observe significant deviations between the implicit and explicit models, with the latter comparing more favourably to available experiments. In particular, we observe a shift of the VPT temperature to larger values as the amount of charged monomers increases. We also find that below the VPT the microgel-counterion complex is almost neutral, while it develops a net charge above the VPT. Interestingly, under these conditions the collapsed microgel still retains a large amount of counterions inside its structure. Since these interesting features cannot be captured by the implicit model, our results show that it is crucial to explicitly include the counterions in order to realistically model ionic thermoresponsive microgels.
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Affiliation(s)
- Giovanni Del Monte
- Physics Department, Sapienza University of Rome, Piazzale A. Moro 2, 00185 Rome, Italy. and CNR-ISC, Sapienza University of Rome, Piazzale A. Moro 2, 00185 Rome, Italy. and Center for Life NanoScience, Istituto Italiano di Tecnologia, Rome, Italy
| | - Andrea Ninarello
- CNR-ISC, Sapienza University of Rome, Piazzale A. Moro 2, 00185 Rome, Italy. and Physics Department, Sapienza University of Rome, Piazzale A. Moro 2, 00185 Rome, Italy.
| | - Fabrizio Camerin
- CNR-ISC, Sapienza University of Rome, Piazzale A. Moro 2, 00185 Rome, Italy. and Department of Basic and Applied Sciences for Engineering, Sapienza University of Rome, via A. Scarpa 14, 00161 Rome, Italy
| | - Lorenzo Rovigatti
- Physics Department, Sapienza University of Rome, Piazzale A. Moro 2, 00185 Rome, Italy. and CNR-ISC, Sapienza University of Rome, Piazzale A. Moro 2, 00185 Rome, Italy.
| | - Nicoletta Gnan
- CNR-ISC, Sapienza University of Rome, Piazzale A. Moro 2, 00185 Rome, Italy. and Physics Department, Sapienza University of Rome, Piazzale A. Moro 2, 00185 Rome, Italy.
| | - Emanuela Zaccarelli
- CNR-ISC, Sapienza University of Rome, Piazzale A. Moro 2, 00185 Rome, Italy. and Physics Department, Sapienza University of Rome, Piazzale A. Moro 2, 00185 Rome, Italy.
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46
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Peng F, Månsson LK, Holm SH, Ghosh S, Carlström G, Crassous JJ, Schurtenberger P, Tegenfeldt JO. A Droplet-Based Microfluidics Route to Temperature-Responsive Colloidal Molecules. J Phys Chem B 2019; 123:9260-9271. [PMID: 31584820 DOI: 10.1021/acs.jpcb.9b07754] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Small clusters of spherical colloids that mimic real molecules, so-called colloidal molecules, hold great promise as building blocks in bottom-up routes to new materials. However, their typical hard sphere nature has hampered their assembly into ordered structures, largely due to a lack of control in the interparticle interactions. To provide easy external control of the interactions, the present work focuses on the preparation of colloidal molecules from temperature-responsive microgel particles that undergo a transition from a soft repulsive to a short-range attractive state as their characteristic volume phase transition temperature (VPTT) is crossed. Preparation of the colloidal molecules starts with the use of a droplet-based microfluidics device to form highly uniform water-in-oil (W/O) emulsion droplets containing, on average and with a narrow distribution, four microgels per droplet. Evaporation of the water then leads to the formation of colloidal molecule-like clusters, which can be harvested following cross-linking and phase transfer. We use a mixture of two types of microgels, one based on poly(N-isopropylacrylamide) (PNIPAM) and the other on poly(N-isopropylmethacrylamide) (PNIPMAM), to prepare bicomponent colloidal molecules, and show that the difference in VPTT between the two allows for induction of attractive interparticle interactions between the PNIPAM interaction sites at temperatures in between the two VPTTs, analogous to the interactions among patchy biomacromolecules such as many proteins.
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Affiliation(s)
| | | | | | | | | | | | - Peter Schurtenberger
- NanoLund , SE-22100 Lund , Sweden.,Lund Institute of advanced Neutron and X-ray Science (LINXS) , Lund University , SE-22370 Lund , Sweden
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Frenzel L, Lehmkühler F, Lokteva I, Narayanan S, Sprung M, Grübel G. Anomalous Dynamics of Concentrated Silica-PNIPAm Nanogels. J Phys Chem Lett 2019; 10:5231-5236. [PMID: 31433650 DOI: 10.1021/acs.jpclett.9b01690] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
We present the structure and dynamics of highly concentrated core-shell nanoparticles composed of a silica core and a poly(N-isoproylacrylamide) (PNIPAm) shell suspended in water. With X-ray photon correlation spectroscopy, we are able to follow dynamical changes over the volume phase transition of PNIPAm at LCST = 32 °C. On raising the temperature beyond LCST, the structural relaxation times continue to decrease. The effect is accompanied by a transition from stretched to compressed exponential shape of the intensity autocorrelation function. Upon further heating, we find a sudden slowing down for the particles in their collapsed state. The q dependence of the relaxation time shows an anomalous change from τc ∝ q-3 to τc ∝ q-1. Small angle X-ray scattering data evidence a temperature-induced transition from repulsive to attractive forces. Our results indicate a temperature-induced phase transition from a colloidal liquid with polymer-driven dynamics toward a colloidal gel.
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Affiliation(s)
- Lara Frenzel
- Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, 22607 Hamburg, Germany
- The Hamburg Centre for Ultrafast Imaging (CUI), Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Felix Lehmkühler
- Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, 22607 Hamburg, Germany
- The Hamburg Centre for Ultrafast Imaging (CUI), Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Irina Lokteva
- Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, 22607 Hamburg, Germany
- The Hamburg Centre for Ultrafast Imaging (CUI), Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Suresh Narayanan
- Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Michael Sprung
- Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, 22607 Hamburg, Germany
| | - Gerhard Grübel
- Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, 22607 Hamburg, Germany
- The Hamburg Centre for Ultrafast Imaging (CUI), Luruper Chaussee 149, 22761 Hamburg, Germany
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48
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Sbeih S, Mohanty PS, Morrow MR, Yethiraj A. Structural parameters of soft PNIPAM microgel particles as a function of crosslink density. J Colloid Interface Sci 2019; 552:781-793. [DOI: 10.1016/j.jcis.2019.05.047] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Revised: 05/14/2019] [Accepted: 05/15/2019] [Indexed: 10/26/2022]
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49
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Kureha T, Minato H, Suzuki D, Urayama K, Shibayama M. Concentration dependence of the dynamics of microgel suspensions investigated by dynamic light scattering. SOFT MATTER 2019; 15:5390-5399. [PMID: 31204747 DOI: 10.1039/c9sm01030k] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The dynamics of colloidal gel particle suspensions, i.e., microgel suspensions, has been investigated by dynamic light scattering (DLS) over a wide concentration range from the (I) dilute (φ < φcp) to the (II) intermediate (φ ≈ φcp) and (III) high concentration regions (φ ≫ φcp), where φ and φcp are the volume fraction of the gel particles in the suspension and the random close packing fraction, φcp ≈ 0.64, respectively. The time-intensity correlation function exhibited a distinct change with increasing φ, i.e., from ergodic behaviour (region I and II) to nonergodic behaviour (region III). A mode transition from translational (region I) to cooperative diffusion (the so-called gel mode) (region II) was also observed due to the soft and deformable nature of the microgels. Different from the dynamics of hard colloidal glass suspensions, the gel mode remained even at φ ≫ φcp. By using the ensemble-averaged time-correlation function, IE, we quantify the relationship between φ and their dynamics, and show that the soft microgels are deswollen in the densely packed state.
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Affiliation(s)
- Takuma Kureha
- Institute for Solid State Physics, The University of Tokyo, Kashiwa 277-8581, Japan.
| | - Haruka Minato
- Graduate School of Textile Science & Technology, Shinshu University, Ueda 386-8567, Japan
| | - Daisuke Suzuki
- Graduate School of Textile Science & Technology, Shinshu University, Ueda 386-8567, Japan and Division of Smart Textile, Institute for Fiber Engineering, Interdisciplinary Cluster for Cutting Edge Research, Shinshu University, Ueda 386-8567, Japan
| | - Kenji Urayama
- Department of Macromolecular Science and Engineering, Kyoto Institute of Technology, Sakyo-ku, Kyoto 606-8585, Japan
| | - Mitsuhiro Shibayama
- Institute for Solid State Physics, The University of Tokyo, Kashiwa 277-8581, Japan.
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50
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Rovigatti L, Gnan N, Ninarello A, Zaccarelli E. Connecting Elasticity and Effective Interactions of Neutral Microgels: The Validity of the Hertzian Model. Macromolecules 2019. [DOI: 10.1021/acs.macromol.9b00099] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Lorenzo Rovigatti
- Dipartimento di Fisica, Sapienza Università di Roma, Piazzale A. Moro 2, 00185 Roma, Italy
- CNR-ISC, Uos Sapienza, Piazzale A. Moro 2, 00185 Roma, Italy
| | - Nicoletta Gnan
- Dipartimento di Fisica, Sapienza Università di Roma, Piazzale A. Moro 2, 00185 Roma, Italy
- CNR-ISC, Uos Sapienza, Piazzale A. Moro 2, 00185 Roma, Italy
| | - Andrea Ninarello
- Dipartimento di Fisica, Sapienza Università di Roma, Piazzale A. Moro 2, 00185 Roma, Italy
- CNR-ISC, Uos Sapienza, Piazzale A. Moro 2, 00185 Roma, Italy
| | - Emanuela Zaccarelli
- Dipartimento di Fisica, Sapienza Università di Roma, Piazzale A. Moro 2, 00185 Roma, Italy
- CNR-ISC, Uos Sapienza, Piazzale A. Moro 2, 00185 Roma, Italy
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