1
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Miles B, Chan DH, Varlas S, Mahato LK, Archer J, Miles RE, Armes SP, Reid JP. Effect of the Addition of Diblock Copolymer Nanoparticles on the Evaporation Kinetics and Final Particle Morphology for Drying Aqueous Aerosol Droplets. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:734-743. [PMID: 38128476 PMCID: PMC10786045 DOI: 10.1021/acs.langmuir.3c02930] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 11/10/2023] [Accepted: 12/05/2023] [Indexed: 12/23/2023]
Abstract
A deeper understanding of the key processes that determine the particle morphologies generated during aerosol droplet drying is highly desirable for spray-drying of powdered pharmaceuticals and foods, predicting the properties of atmospheric particles, and monitoring disease transmission. Particle morphologies are affected by the drying kinetics of the evaporating droplets, which are in turn influenced by the composition of the initial droplet as well as the drying conditions. Herein, we use polymerization-induced self-assembly (PISA) to prepare three types of sterically stabilized diblock copolymer nanoparticles comprising the same steric stabilizer block and differing core blocks with z-average diameters ranging from 32 to 238 nm. These well-defined nanoparticles enable a systematic investigation of the effect of the nanoparticle size and composition on the drying kinetics of aqueous aerosol droplets (20-28 μm radius) and the final morphology of the resulting microparticles. A comparative kinetics electrodynamic balance was used to obtain evaporation profiles for 10 examples of nanoparticles at a relative humidity (RH) of 0, 45, or 65%. Nanoparticles comprising the same core block with mean diameters of 32, 79, and 214 nm were used to produce microparticles, which were dried under different RH conditions in a falling droplet column. Scanning electron microscopy was used to examine how the drying kinetics influenced the final microparticle morphology. For dilute droplets, the chemical composition of the nanoparticles had no effect on the evaporation rate. However, employing smaller nanoparticles led to the formation of dried microparticles with a greater degree of buckling.
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Affiliation(s)
| | - Derek H.H. Chan
- Dainton
Building, Department of Chemistry, University
of Sheffield, Brook Hill, Sheffield S3 7HF, South Yorkshire, U.K.
| | - Spyridon Varlas
- Dainton
Building, Department of Chemistry, University
of Sheffield, Brook Hill, Sheffield S3 7HF, South Yorkshire, U.K.
| | - Lukesh K. Mahato
- School
of Chemistry, University of Bristol, Bristol BS8 1TS, U.K.
| | - Justice Archer
- School
of Chemistry, University of Bristol, Bristol BS8 1TS, U.K.
| | | | - Steven P. Armes
- Dainton
Building, Department of Chemistry, University
of Sheffield, Brook Hill, Sheffield S3 7HF, South Yorkshire, U.K.
| | - Jonathan P. Reid
- School
of Chemistry, University of Bristol, Bristol BS8 1TS, U.K.
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2
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Yetkin M, Wani YM, Kritika K, Howard MP, Kappl M, Butt HJ, Nikoubashman A. Structure Formation in Supraparticles Composed of Spherical and Elongated Particles. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:1096-1108. [PMID: 38153401 DOI: 10.1021/acs.langmuir.3c03410] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2023]
Abstract
We studied the evaporation-induced formation of supraparticles from dispersions of elongated colloidal particles using experiments and computer simulations. Aqueous droplets containing a dispersion of ellipsoidal and spherical polystyrene particles were dried on superamphiphobic surfaces at different humidity values that led to varying evaporation rates. Supraparticles made from only ellipsoidal particles showed short-range lateral ordering at the supraparticle surface and random orientations in the interior regardless of the evaporation rate. Particle-based simulations corroborated the experimental observations in the evaporation-limited regime and showed an increase in the local nematic ordering as the diffusion-limited regime was reached. A thin shell of ellipsoids was observed at the surface when supraparticles were made from binary mixtures of ellipsoids and spheres. Image analysis revealed that the supraparticle porosity increased with an increasing aspect ratio of the ellipsoids.
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Affiliation(s)
- Melis Yetkin
- Department of Physics at Interfaces, Max-Planck Institute for Polymer Research, Ackermannweg 10, Mainz 55128, Germany
| | - Yashraj M Wani
- Institute of Physics, Johannes Gutenberg University of Mainz, Staudingerweg 7, Mainz 55128, Germany
| | - Kritika Kritika
- Institute of Physics, Johannes Gutenberg University of Mainz, Staudingerweg 7, Mainz 55128, Germany
- Leibniz-Institut für Polymerforschung Dresden e.V., Hohe Straße 6, Dresden 01069, Germany
- Institut für Theoretische Physik, Technische Universität Dresden, Dresden 01069, Germany
| | - Michael P Howard
- Department of Chemical Engineering, Auburn University, Auburn, Alabama 36849, United States
| | - Michael Kappl
- Department of Physics at Interfaces, Max-Planck Institute for Polymer Research, Ackermannweg 10, Mainz 55128, Germany
| | - Hans-Jürgen Butt
- Department of Physics at Interfaces, Max-Planck Institute for Polymer Research, Ackermannweg 10, Mainz 55128, Germany
| | - Arash Nikoubashman
- Institute of Physics, Johannes Gutenberg University of Mainz, Staudingerweg 7, Mainz 55128, Germany
- Leibniz-Institut für Polymerforschung Dresden e.V., Hohe Straße 6, Dresden 01069, Germany
- Institut für Theoretische Physik, Technische Universität Dresden, Dresden 01069, Germany
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3
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Mehta S, Bahadur J, Sharma SK, Sen D. Interparticle interaction-dependent jamming in colloids: insights into glass transition and morphology modulation during rapid evaporation-induced assembly. SOFT MATTER 2024; 20:375-387. [PMID: 38099855 DOI: 10.1039/d3sm01186k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2024]
Abstract
Understanding the role of interparticle interactions in jamming phenomena is essential for gaining insights into the intriguing glass transition behavior observed in atomic and molecular systems. In this study, we investigate the jamming behavior of colloids with tunable interparticle interactions during evaporation-induced assembly (EIA). By manipulating the interaction among charged colloids using cationic polyethyleneimine (PEI) through electro-sorption and subsequent free polymer induced repulsion, we observe distinct jamming behavior in silica colloids during EIA, depending on the interparticle interactions. Silica colloids with strong repulsive interactions exhibit a repulsive colloidal glass state with a volume fraction of silica colloids in supraparticle ϕ ∼ 0.70. On the other hand, PEI-mediated attractive interactions among silica colloids lead to an attractive colloidal glass phase with a significantly lower ϕ ∼ 0.43. Free polymer induced repulsion of colloids at higher PEI concentration once again results in a repulsive glassy state with ϕ ∼ 0.61. Furthermore, we revealed that interparticle interactions not only influence the jamming behavior but also play a significant role in shaping the morphology of self-assembled structures during EIA, and the assembled structure undergoes a morphological reentrant transition from a doughnut-like shape to a spherical form and again back to a doughnut-like configuration. Jamming-dependent evolution of micropores and dynamics of the confined PEI have been probed using positron annihilation lifetime spectroscopy (PALS) and broadband dielectric spectroscopy (BDS). PALS reveals distinct variations in the micropores of the supraparticles with different PEI loadings, confirming the impact of jamming on the evolution of the micropores within the supraparticles. BDS measurements uncover non-monotonic dynamics of PEI molecules confined in the evolved pore network. It is revealed that the reentrant jamming behavior of colloids, modulated by PEI, holds profound significance for the long-term stability of supraparticles.
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Affiliation(s)
- Swati Mehta
- Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400085, India.
- Homi Bhabha National Institute, Anushaktinagar, Mumbai 400094, India
| | - Jitendra Bahadur
- Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400085, India.
- Homi Bhabha National Institute, Anushaktinagar, Mumbai 400094, India
| | - Sandeep K Sharma
- Radiochemistry Division, Bhabha Atomic Research Centre, Mumbai, 400085, India
- Homi Bhabha National Institute, Anushaktinagar, Mumbai 400094, India
| | - Debasis Sen
- Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400085, India.
- Homi Bhabha National Institute, Anushaktinagar, Mumbai 400094, India
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4
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Mehta S, Bahadur J, Sen D, Nechiyil D, Bhatt H, Kumar N, Prakash J. Polyethyleneimine-assisted formation of Ag-SiO 2 hybrid microspheres for H 2O 2 sensing and SERS applications. RSC Adv 2023; 13:29086-29098. [PMID: 37800133 PMCID: PMC10548522 DOI: 10.1039/d3ra04095j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2023] [Accepted: 09/15/2023] [Indexed: 10/07/2023] Open
Abstract
Herein, we report a simple, cost-effective, and eco-friendly approach for producing polyethyleneimine (PEI)-assisted silver nanoparticle-supported silica microspheres through evaporation-induced assembly (EIA). The silica-PEI microspheres obtained through EIA consisted of highly trapped PEI molecules owing to their electrosorption onto oppositely charged silica colloids. The trapped PEI molecules in the microspheres played a crucial role in linking silver ions to form silver ion-PEI complexes, which were then reduced to form silver nanoparticles. Further, the complex interactions between PEI and silica colloids led to enhanced porosity in the microspheres, enabling the efficient adsorption of Ag ions. The characterization of the Ag-SiO2 microspheres was carried out using various techniques, including field-emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX) spectroscopy, X-ray diffraction (XRD), small-angle X-ray scattering (SAXS), and Fourier transform infrared (FTIR) spectroscopy, which confirmed the successful formation of Ag nanoparticles on microspheres, and a plausible formation mechanism is elucidated. The Ag-SiO2 microspheres exhibited good sensing properties for hydrogen peroxide (H2O2), with an estimated limit of detection of 1.08 mM and a sensitivity of 0.033 μA mM-1 mm-2. The microspheres were also used as a surface-enhanced Raman scattering (SERS) substrate, which demonstrated high sensitivity in detecting rhodamine 6G down to a concentration of 2 × 10-6 M. The present approach elucidates a promising alternative to conventional methods that face challenges, such as scalability issues, complex and cumbersome synthesis procedures, and the use of strong reducing agents. With the potential for industrial-level scalability, this method offers a viable strategy for producing Ag-SiO2 microspheres with possible applications in biomedical and sensing technologies.
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Affiliation(s)
- Swati Mehta
- Solid State Physics Division, Bhabha Atomic Research Centre Mumbai 400085 India
- Homi Bhabha National Institute Mumbai 400094 India
| | - Jitendra Bahadur
- Solid State Physics Division, Bhabha Atomic Research Centre Mumbai 400085 India
- Homi Bhabha National Institute Mumbai 400094 India
| | - Debasis Sen
- Solid State Physics Division, Bhabha Atomic Research Centre Mumbai 400085 India
- Homi Bhabha National Institute Mumbai 400094 India
| | - Divya Nechiyil
- Materials Group, Bhabha Atomic Research Centre Mumbai 400085 India
| | - H Bhatt
- High Pressure and Synchrotron Radiation Physics Division, Bhabha Atomic Research Centre Mumbai 400085 India
- Homi Bhabha National Institute Mumbai 400094 India
| | - Naveen Kumar
- Atomic and Molecular Physics Division, Bhabha Atomic Research Centre Mumbai 400085 India
| | - Jyoti Prakash
- Homi Bhabha National Institute Mumbai 400094 India
- Materials Group, Bhabha Atomic Research Centre Mumbai 400085 India
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5
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Li Y, Xu J, Yang H. Pickering Emulsion Droplet-Derived Multicompartmentalized Microspheres for Innovative Applications. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:5621-5630. [PMID: 37058608 DOI: 10.1021/acs.langmuir.3c00135] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Multicompartmentalized microspheres with multilevel and complex interior structures have great potential in practical applications due to their cell-like structures and microscale dimension. The Pickering emulsion droplet-confined synthesis route has been demonstrated to be a promising strategy for fabricating multicompartmentalized microspheres. Since Pickering emulsion-templated formation of hollow microspheres is an interface-directed process in which the growth of shells occurs at the oil/water interface and the confined space of Pickering emulsion droplet accommodates a variety of behaviors, such as surfactant-guided assembly growth, confined pyrolysis transformation, tritemplated growth, and bottom-up assembly, the independent and free regulation of the interface and internal structure of microspheres is allowed. In this Perspective, we highlight the recent progress in the synthesis of microparticles with tunable interior structures via the Pickering emulsion droplet-based approach. And we delve into the innovative applications of these multilevel-structured microparticles benefiting from their biomimetic multicompartments. Finally, some fundamental challenges and opportunities are identified for regulating the interior structure within microspheres and promoting practical applications by virtue of the Pickering emulsion droplet-confined synthesis pathway.
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Affiliation(s)
- Yanyan Li
- School of Chemistry and Chemical Engineering, Shanxi University, Taiyuan 030006, China
| | - Jie Xu
- State Key Laboratory of New Textile Materials and Advanced Processing Technology, School of Materials Science and Engineering, Wuhan Textile University, Wuhan 430200, China
| | - Hengquan Yang
- School of Chemistry and Chemical Engineering, Shanxi University, Taiyuan 030006, China
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6
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Bamboriya OP, Tirumkudulu MS. Universality in the buckling behavior of drying suspension drops. SOFT MATTER 2023; 19:2605-2611. [PMID: 36947449 DOI: 10.1039/d2sm01688e] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Fast evaporation of particle-suspension drops results in complex morphologies of the final dried granules. Understanding the morphological transformations is important to industrial processes such as spray drying where droplets of particulate suspensions are dried at a fast rate to produce granules of thermally sensitive materials. The transformation of an initial spherical shell to complex morphologies of the final dried granule has been attributed to the buckling of particle-packed shells. Here, we demonstrate a universal scaling law for buckling that depends on the particle size, hardness, particle packing and size of drying drop. The critical transition for buckling is set by a dimensionless number that measures the competition between the compressive stress generated by capillary forces and the elastic strength of the packing. The same dimensionless number is also responsible for cracking of drying colloidal films, suggesting a universality in the mechanical behaviour of particle packings saturated with a solvent. These results should enable design of hierarchically structured, buckle-free granules with varying porosity, surface composition and internal structure.
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Affiliation(s)
- Om Prakash Bamboriya
- Department of Chemical Engineering, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India.
| | - Mahesh S Tirumkudulu
- Department of Chemical Engineering, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India.
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7
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Chen H, Zhang Y, Wang H, Dong X, Zang D. Evaporation Caused Invaginations of Acoustically Levitated Colloidal Droplets. NANOMATERIALS (BASEL, SWITZERLAND) 2022; 13:133. [PMID: 36616043 PMCID: PMC9824602 DOI: 10.3390/nano13010133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/27/2022] [Revised: 12/18/2022] [Accepted: 12/21/2022] [Indexed: 06/17/2023]
Abstract
Controlled buckling of colloidal droplets via acoustic levitation plays an important role in pharmaceutical, coating, and material self-assembly. In this study, the evaporation process of PTFE colloidal droplets with two particle concentrations (60 wt% and 20 wt%) was investigated under acoustic levitation. We report the occurrence of surface invagination caused by evaporation. For the high particle concentration droplet, the upper surface was invaginated, eventually forming a bowl-shaped structure. While for the low particle concentration droplet, both the upper and lower surfaces of the droplet were invaginated, resulting in a doughnut-like structure. For the acoustically levitated oblate spherical droplet, the dispersant loss at the equatorial area of the droplet is greater than that at the two poles. Therefore, the thickness of the solid shell on the surface of the droplet was not uniform, resulting in invagination at the weaker pole area. Moreover, once the droplet surface was buckling, the hollow cavity on the droplet surface would absorb the sound energy and results in strong positive acoustic radiation pressure at bottom of the invagination, thus further prompting the invagination process.
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Affiliation(s)
- Hongyue Chen
- MOE Key Laboratory of Material Physics and Chemistry under Extraordinary Conditions, School of Physical Science and Technology, Northwestern Polytechnical University, Xi’an 710129, China
| | - Yongjian Zhang
- Shaanxi Key Laboratory of Surface Engineering and Remanufacturing, School of Mechanical and Material Engineering, Xi’an University, Xi’an 710065, China
| | - Heyi Wang
- Shaanxi Key Laboratory of Surface Engineering and Remanufacturing, School of Mechanical and Material Engineering, Xi’an University, Xi’an 710065, China
| | - Xin Dong
- Shaanxi Key Laboratory of Surface Engineering and Remanufacturing, School of Mechanical and Material Engineering, Xi’an University, Xi’an 710065, China
| | - Duyang Zang
- MOE Key Laboratory of Material Physics and Chemistry under Extraordinary Conditions, School of Physical Science and Technology, Northwestern Polytechnical University, Xi’an 710129, China
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8
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Mehta S, Bahadur J, Sen D, Singh S, Polshettiwar V. Polyethylenimine assisted non-monotonic jamming of colloids during evaporation induced assembly and its implication on CO 2 sorption characteristics. SOFT MATTER 2022; 18:5114-5125. [PMID: 35766282 DOI: 10.1039/d2sm00685e] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
We report a detailed study of hierarchically organized silica-polyethylenimine (PEI) microspheres achieved through evaporation-induced assembly. Due to complex interactions between oppositely-charged silica nanoparticles and PEI, non-monotonic jamming of the colloidal particles is manifested. With an increase in the polymer concentration, the local volume fraction of the silica particles decreases from 0.68 to 0.43 and then increases to 0.55 with further increase. The unusual jamming behaviour of the silica colloids in the presence of PEI provides an avenue for immobilizing PEI without reducing the porosity and specific area in contrast to the conventional impregnation approach. The resultant composite microspheres show good thermal stability and CO2 sorption characteristics. For a 33 wt% PEI loading, the microspheres exhibit a significant CO2 capture capacity of 65 mg g-1 even at room temperature and it is increased to 90 mg g-1 at 75 °C. The variation in the CO2 capture capacity at 0 °C as a function of PEI loading also demonstrated the signature of non-monotonicity owing to the structural modification in the silica-PEI microspheres. The composite microspheres demonstrated fast adsorption kinetics reaching 70% of the total capture capacity in one minute during the CO2 capture. The CO2 cycling adsorption-desorption studies showed good regeneration capability up to 20 cycles.
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Affiliation(s)
- Swati Mehta
- Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai, 400085, India.
- Homi Bhabha National Institute, Anushaktinagar, Mumbai, 400094, India
| | - Jitendra Bahadur
- Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai, 400085, India.
- Homi Bhabha National Institute, Anushaktinagar, Mumbai, 400094, India
| | - Debasis Sen
- Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai, 400085, India.
- Homi Bhabha National Institute, Anushaktinagar, Mumbai, 400094, India
| | - Saideep Singh
- Department of Chemical Science, Tata Institute of Fundamental Research, Mumbai, 400001, India
| | - Vivek Polshettiwar
- Department of Chemical Science, Tata Institute of Fundamental Research, Mumbai, 400001, India
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9
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Biswas P, Sen D, Prasher M, Sarkar SK, Dasgupta K. Confinement driven anomalous freezing in nano porous spray dried microspheres. NANOTECHNOLOGY 2021; 32:385707. [PMID: 34116521 DOI: 10.1088/1361-6528/ac0ab6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Accepted: 06/11/2021] [Indexed: 06/12/2023]
Abstract
One-step evaporative jamming of colloidal silica particles in contact-free spray droplets resulted in well-defined powder micro-granules with interstitial nanopores. This paper reports the anomalous freezing behaviour of confined water in the microspheres synthesized using spray drying. It has been revealed that the freezing point of water in these microspheres gets significantly lowered (∼-45 °C) owing to the confinement effect. Thermoporometry results are corroborated with the structural details obtained using complementary techniques of gas adsorption measurements and small-angle x-ray scattering.
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Affiliation(s)
- Priyanka Biswas
- Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai-400085, India
- Homi Bhabha National Institute, Mumbai-400094, India
| | - Debasis Sen
- Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai-400085, India
- Homi Bhabha National Institute, Mumbai-400094, India
| | - Meenu Prasher
- Materials Science Division, Bhabha Atomic Research Centre, Mumbai-400085, India
| | - Sudip Kumar Sarkar
- Materials Science Division, Bhabha Atomic Research Centre, Mumbai-400085, India
| | - Kinshuk Dasgupta
- Homi Bhabha National Institute, Mumbai-400094, India
- Glass and Advanced Materials Division, Materials Group, Bhabha Atomic Research Centre, Mumbai-400085, India
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10
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Biswas P, Sen D, Bouwman W. Structural characterization of spray-dried microgranules by spin-echo small-angle neutron scattering. POWDER TECHNOL 2021. [DOI: 10.1016/j.powtec.2020.10.035] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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11
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Archer J, Walker JS, Gregson FKA, Hardy DA, Reid JP. Drying Kinetics and Particle Formation from Dilute Colloidal Suspensions in Aerosol Droplets. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:12481-12493. [PMID: 32975425 DOI: 10.1021/acs.langmuir.0c01830] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Industrial processes such as spray drying of pharmaceutical and food products often involve the drying of aerosol droplets containing colloidal suspensions into powdered microparticles of desired properties. The morphology and surface properties of the final dry products/microparticles obtained after the drying process are strongly influenced by the parameters of the initial aerosol droplet composition and the drying conditions. In particular, the final dry microparticle morphology can be dependent on the dimensionless Péclet number (Pe), which expresses the relative competition between the diffusion of the dispersed particles within the droplet and the rate of solvent loss via evaporation. In this work, we examine how control over the gas phase drying conditions and initial aerosol droplet composition can be used to influence the aerosol droplet drying kinetics in the gas phase for a range of Péclet numbers. We used a single-particle levitation instrument, the electrodynamic balance, to measure the drying kinetics of colloidal silica droplets (0.10-0.60% v/v) under controlled gas phase drying conditions of temperature (263-326 K) and relative humidity (0-90%) and obtained Péclet numbers ranging from 4.05 to 184.5. We demonstrate that, for aerosol droplets with initially dilute feed colloid concentrations and within the constant evaporation regime, the starting composition does not strongly influence the solvent evaporation rate with the included nanoparticles (NPs) acting as spectators. However, the gas phase drying conditions, temperature, and relative humidity, directly influence the droplet temperature via evaporative cooling as well as the droplet drying kinetics and the final dry microparticle properties. With a priori knowledge of the droplet drying kinetics from the single droplet measurements, we further demonstrate the possibility of tailoring the morphology of the dried microparticles. Dried silica microparticles collected at Pe = 23.8 had dense spherical morphologies, while those at the highest Pe = 180.0 had crumpled surface morphologies with a transition in morphology between these limiting Pe values. Our results extend the fundamental understanding of the mechanisms controlling the drying of aerosol droplets in colloidal suspensions across a wide range of application areas extending from spray drying to the drying of respiratory fluid droplets containing bacteria and viruses and the drying of atmospheric aerosol droplets.
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Affiliation(s)
- Justice Archer
- School of Chemistry, University of Bristol, Bristol BS8 1TS, U.K
| | - Jim S Walker
- School of Chemistry, University of Bristol, Bristol BS8 1TS, U.K
| | | | - Daniel A Hardy
- School of Chemistry, University of Bristol, Bristol BS8 1TS, U.K
| | - Jonathon P Reid
- School of Chemistry, University of Bristol, Bristol BS8 1TS, U.K
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12
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Boel E, Koekoekx R, Dedroog S, Babkin I, Vetrano MR, Clasen C, Van den Mooter G. Unraveling Particle Formation: From Single Droplet Drying to Spray Drying and Electrospraying. Pharmaceutics 2020; 12:pharmaceutics12070625. [PMID: 32635464 PMCID: PMC7408114 DOI: 10.3390/pharmaceutics12070625] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 06/26/2020] [Accepted: 06/29/2020] [Indexed: 12/25/2022] Open
Abstract
Spray drying and electrospraying are well-established drying processes that already have proven their value in the pharmaceutical field. However, there is currently still a lack of knowledge on the fundamentals of the particle formation process, thereby hampering fast and cost-effective particle engineering. To get a better understanding of how functional particles are formed with respect to process and formulation parameters, it is indispensable to offer a comprehensive overview of critical aspects of the droplet drying and particle formation process. This review therefore closely relates single droplet drying to pharmaceutical applications. Although excellent reviews exist of the different aspects, there is, to the best of our knowledge, no single review that describes all steps that one should consider when trying to engineer a certain type of particle morphology. The findings presented in this article have strengthened the predictive value of single droplet drying for pharmaceutical drying applications like spray drying and electrospraying. Continuous follow-up of the particle formation process in single droplet drying experiments hence allows optimization of manufacturing processes and particle engineering approaches and acceleration of process development.
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Affiliation(s)
- Eline Boel
- Department of Pharmaceutical and Pharmacological Sciences, Drug Delivery and Disposition, KU Leuven, 3000 Leuven, Belgium; (E.B.); (S.D.)
| | - Robin Koekoekx
- Department of Chemical Engineering, Soft Matter, Rheology and Technology, KU Leuven, 3001 Leuven, Belgium; (R.K.); (I.B.); (C.C.)
| | - Sien Dedroog
- Department of Pharmaceutical and Pharmacological Sciences, Drug Delivery and Disposition, KU Leuven, 3000 Leuven, Belgium; (E.B.); (S.D.)
| | - Iurii Babkin
- Department of Chemical Engineering, Soft Matter, Rheology and Technology, KU Leuven, 3001 Leuven, Belgium; (R.K.); (I.B.); (C.C.)
| | - Maria Rosaria Vetrano
- Department of Mechanical Engineering, Applied Mechanics and Energy Conversion, KU Leuven, 3001 Leuven, Belgium;
| | - Christian Clasen
- Department of Chemical Engineering, Soft Matter, Rheology and Technology, KU Leuven, 3001 Leuven, Belgium; (R.K.); (I.B.); (C.C.)
| | - Guy Van den Mooter
- Department of Pharmaceutical and Pharmacological Sciences, Drug Delivery and Disposition, KU Leuven, 3000 Leuven, Belgium; (E.B.); (S.D.)
- Correspondence: ; Tel.: +32-16-330304
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13
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Bahadur J, Das A, Sen D. Evaporation-induced structural evolution of the lamellar mesophase: a time-resolved small-angle X-ray scattering study. J Appl Crystallogr 2019. [DOI: 10.1107/s1600576719011671] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Time-resolved small-angle X-ray scattering (SAXS) measurements have been carried out using the newly developed SAXS beamline at the Indus-2 synchrotron source to study the evaporation-induced structural evolution of the lamellar mesophase. An aqueous dispersion of sodium dodecyl sulfate (SDS) of ∼0.60 volume fraction at room temperature results in a gel phase due to random jamming of the lamellar structured entities. Thermal analysis of SDS in the powder phase shows three distinct phenomena corresponding to evaporation of free and bound water, followed by thermal dissociation of SDS molecules. Time-resolved in situ SAXS measurements during evaporation of the gel under ambient conditions reveal two regimes of structural evolution of the lamellar phase. The evaporation rate in the first phase of evaporation up to 60 min is roughly six times faster than that in the second phase. A plausible mechanism is proposed to explain this behaviour. The intrusion of water molecules into layers sandwiched between polar head groups forms an additional 7 Å thick layer of water molecules, leading to an increase in the distance between the head groups. The evaporation of the water molecules in the first phase up to 60 min causes a reduction in the lamellar thickness of ∼3 Å. Subsequent evaporation of water molecules in the second phase is quite slow owing to the higher binding energy of these water molecules and the low permeability caused by the reduced lamellar thickness after the first phase of evaporation. The swelling behaviour of the lamellar structure under ambient conditions is found to be reversible and the powder-phase structure is observed after a few days of evaporation of the gel phase.
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14
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Mondal R, Das A, Sen D, Satapathy DK, Basavaraj MG. Spray drying of colloidal dispersions containing ellipsoids. J Colloid Interface Sci 2019; 551:242-250. [DOI: 10.1016/j.jcis.2019.05.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Revised: 05/01/2019] [Accepted: 05/03/2019] [Indexed: 10/26/2022]
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15
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Das A, Sen D, Bahadur J, Subramanian M. Confinement induced formation of silver nanoparticles in self-assembled micro-granules. Colloids Surf A Physicochem Eng Asp 2019. [DOI: 10.1016/j.colsurfa.2019.05.082] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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16
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Shang C, Wu Z, Wu WD, Chen XD. Chemical Crosslinking Assembly of ZSM-5 Nanozeolites into Uniform and Hierarchically Porous Microparticles for High-Performance Acid Catalysis. ACS APPLIED MATERIALS & INTERFACES 2019; 11:16693-16703. [PMID: 30983328 DOI: 10.1021/acsami.9b01681] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Hierarchically porous zeolites combining the advantages of desirable mass transport of nanozeolites and easy separation and handling of micro-zeolites are ideal candidates in catalytic applications. Facile routes for the assembly of zeolite microparticles with hierarchical porosity and high mechanical strength are much expected. Herein, based on a microfluidic jet spray drying technology, we report a facile and scalable chemical crosslinking assembly strategy for the synthesis of hierarchical zeolite microparticles by directly using the conventional as-synthesized nanozeolite suspension as a precursor. This route not only avoids the energy-intensive centrifugal separation process of nanozeolites but also significantly increases the uniformity and mechanical strength of the microparticles. The soluble aluminosilicate species act as a stabilizer to improve the droplet stability during the drying process and then as a "cross-linker" to chemically bind and interconnect zeolite nanoparticles to form robust bodies after drying and calcination. Zeolite microparticles with variable morphologies (spherical, bowl-like, and dimpled) and uniform and controllable sizes (from 70 to 108 μm) can be obtained by adjusting the experimental parameters. The particle formation mechanism is discussed based on the zeolite microparticles obtained from the purified nanozeolite suspension as a control. The zeolite microparticles possess emerged uniform mesopores (∼6 nm) and a well-maintained high surface area, large pore volume, high microporosity, and strong acidity of the original nanozeolites. As a result, they exhibit excellent acid catalytic performances in acetolysis of epichlorohydrin and catalytic cracking of low-density polyethylene, far better than those of the commercial ZSM-5.
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Affiliation(s)
- Chao Shang
- School of Chemical and Environmental Engineering, College of Chemistry, Chemical Engineering and Materials Science , Soochow University , Suzhou , Jiangsu 215123 , P. R. China
| | - Zhangxiong Wu
- School of Chemical and Environmental Engineering, College of Chemistry, Chemical Engineering and Materials Science , Soochow University , Suzhou , Jiangsu 215123 , P. R. China
| | - Winston Duo Wu
- School of Chemical and Environmental Engineering, College of Chemistry, Chemical Engineering and Materials Science , Soochow University , Suzhou , Jiangsu 215123 , P. R. China
| | - Xiao Dong Chen
- School of Chemical and Environmental Engineering, College of Chemistry, Chemical Engineering and Materials Science , Soochow University , Suzhou , Jiangsu 215123 , P. R. China
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17
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Biswas P, Sen D, Ha JM, Choi SM. Anisotropic interaction driven surface modulation on spray-dried microgranules. J Colloid Interface Sci 2018; 538:149-158. [PMID: 30502536 DOI: 10.1016/j.jcis.2018.11.056] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Revised: 11/09/2018] [Accepted: 11/13/2018] [Indexed: 11/16/2022]
Abstract
Rapid evaporation of solvent from spray colloidal droplets induces directed self-assembly among the nanoparticles, eventually interlocking them into correlated granular structures. In this work, it is demonstrated that anisotropy in colloidal interparticle interaction plays a key role in governing the surface topology of spray-dried granules. Colloidal dispersion comprised of spherical nanosilica (NS) and cylindrical carbon nanotubes (CNT) was chosen as a model system in this regard. For identical polarities of the colloidal components, granules with prominent wrinkle-like modulations are obtained, which is in drastic contrast with the case of opposite polarities. The extent of surface modulation depends on the relative concentration of CNT with respective to NS. A plausible mechanism for the formation of surface modulation is elucidated on the basis of the evolving anisotropic interparticle interactions during assembly. Electron microscopy, small-angle scattering, Raman spectroscopic techniques have been used for quantitative characterization of these micro-granules.
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Affiliation(s)
- Priyanka Biswas
- Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400085, India; Homi Bhabha National Institute, Mumbai 400094, India
| | - Debasis Sen
- Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400085, India; Homi Bhabha National Institute, Mumbai 400094, India.
| | - Jae-Min Ha
- Department of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology, Daejeon 305701, Korea
| | - Sung-Min Choi
- Department of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology, Daejeon 305701, Korea
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18
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Abstract
Colloidal transformation based on simple physicochemical processes has produced a wide variety of functional structures for different applications. But the lack of local selectivity of conventional transformation methods makes the fabrication of nanodevices with desired optical properties challenging. Here, we use a laser beam to transform spherical polystyrene (PS) beads into bull's eye-shaped nanopatterns or concentric nanorings, depending on the time of irradiation. The final morphologies are dependent on the size of the PS beads and the dielectric nature of the substrates. The simulated near field features show that it is the selective hollowing of PS beads that results in collapsing and buckling of the shells. This understanding provides a new route towards unconventional colloidal nanostructures and defect engineering in 2D photonic crystals that can be locally and selectively controlled by light.
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Affiliation(s)
- Shuangshuang Wang
- Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education of China, School of Physics and Technology, Wuhan University, China.
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19
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Vertruyen B, Eshraghi N, Piffet C, Bodart J, Mahmoud A, Boschini F. Spray-Drying of Electrode Materials for Lithium- and Sodium-Ion Batteries. MATERIALS 2018; 11:ma11071076. [PMID: 29941820 PMCID: PMC6073579 DOI: 10.3390/ma11071076] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 06/20/2018] [Accepted: 06/21/2018] [Indexed: 11/16/2022]
Abstract
The performance of electrode materials in lithium-ion (Li-ion), sodium-ion (Na-ion) and related batteries depends not only on their chemical composition but also on their microstructure. The choice of a synthesis method is therefore of paramount importance. Amongst the wide variety of synthesis or shaping routes reported for an ever-increasing panel of compositions, spray-drying stands out as a versatile tool offering demonstrated potential for up-scaling to industrial quantities. In this review, we provide an overview of the rapidly increasing literature including both spray-drying of solutions and spray-drying of suspensions. We focus, in particular, on the chemical aspects of the formulation of the solution/suspension to be spray-dried. We also consider the post-processing of the spray-dried precursors and the resulting morphologies of granules. The review references more than 300 publications in tables where entries are listed based on final compound composition, starting materials, sources of carbon etc.
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Affiliation(s)
- Benedicte Vertruyen
- GREENMAT, CESAM Research Unit, University of Liege, Chemistry Institute B6, Quartier Agora, Allée du 6 août, 13, B-4000 Liege, Belgium.
| | - Nicolas Eshraghi
- GREENMAT, CESAM Research Unit, University of Liege, Chemistry Institute B6, Quartier Agora, Allée du 6 août, 13, B-4000 Liege, Belgium.
| | - Caroline Piffet
- GREENMAT, CESAM Research Unit, University of Liege, Chemistry Institute B6, Quartier Agora, Allée du 6 août, 13, B-4000 Liege, Belgium.
| | - Jerome Bodart
- GREENMAT, CESAM Research Unit, University of Liege, Chemistry Institute B6, Quartier Agora, Allée du 6 août, 13, B-4000 Liege, Belgium.
| | - Abdelfattah Mahmoud
- GREENMAT, CESAM Research Unit, University of Liege, Chemistry Institute B6, Quartier Agora, Allée du 6 août, 13, B-4000 Liege, Belgium.
| | - Frederic Boschini
- GREENMAT, CESAM Research Unit, University of Liege, Chemistry Institute B6, Quartier Agora, Allée du 6 août, 13, B-4000 Liege, Belgium.
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20
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Sen D, Das A, Bahadur J, Choudhury N. Dynamic modulation of inter-particle correlation during colloidal assembly in a confined medium: revealed by real time SAXS. Phys Chem Chem Phys 2018; 20:13271-13278. [PMID: 29457174 DOI: 10.1039/c8cp00401c] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Using real time small-angle X-ray scattering, we ellucidate a hitherto unobserved non-monotonic evolution of inter-particle correlation while colloidal particles assemble across pore boundary in a confined medium under influence of solvent evaporation. Time variation of local volume fraction of the particles passes through distinct modulation prior to reaching equilibrium. It has been demonstrated that the amplitude of oscillation depends strongly on size of the assembling particles. We comprehend such non-linear temporal evolution of particle correlation through density functional theory and molecular dynamics simulation.
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Affiliation(s)
- Debasis Sen
- Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai-400085, India. and Homi Bhabha National Institute, Anushaktinagar, Mumbai-400094, India
| | - Avik Das
- Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai-400085, India. and Homi Bhabha National Institute, Anushaktinagar, Mumbai-400094, India
| | - Jitendra Bahadur
- Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai-400085, India.
| | - Niharendu Choudhury
- Theoretical Chemistry Section, Bhabha Atomic Research Centre, Mumbai-400085, India and Homi Bhabha National Institute, Anushaktinagar, Mumbai-400094, India
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21
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Lu Z, Rezk A, Jativa F, Yeo L, Zhang X. Dissolution dynamics of a suspension droplet in a binary solution for controlled nanoparticle assembly. NANOSCALE 2017; 9:13441-13448. [PMID: 28702595 DOI: 10.1039/c7nr02704d] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Toroidal microstructures of nanocolloidal assemblies promise important applications ranging from sensing, catalysis, drug delivery, and separation. In this work, we will first investigate the rich dissolution dynamics of a droplet comprising a nanoparticle suspension in a binary solution, and then show that the dissolution dynamics can be a potential approach to assembling a wide range of colloids with microtoroids. As the sessile droplet dissolves in the binary solution of miscible and immiscible solvents, two simultaneous effects are observed: if the dissolution rate is sufficiently high under large concentrations of the cosolvent in the surrounding solution, a strong plume emanates from the droplet pole as a consequence of a body force (i.e. the Korteweg force) driven by the chemical potential gradient between the water in the droplet and in the surrounding phase. Concurrently, the convection drives internal recirculation flow dynamics, leading to the inversion of the droplet curvature such that its initially spherical shape gradually contracts to evolve into a toroidal structure. We further demonstrate that the dissolution of a suspension droplet is an approach to assemble nanoparticles into toroidal microstructures. The resultant toroidal shapes are extrinsically governed by the composition and the geometrical confinement of the surrounding solution phase.
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Affiliation(s)
- Ziyang Lu
- Soft Matter & Interfaces Group, School of Engineering, RMIT University, Melbourne, VIC 3001, Australia.
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22
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Biswas P, Sen D, Mazumder S, Ramkumar J. Porous microcapsules comprised inter-locked nano-particles by evaporation-induced assembly: Evaluation of dye sorption. Colloids Surf A Physicochem Eng Asp 2017. [DOI: 10.1016/j.colsurfa.2017.01.091] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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23
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Biswas P, Sen D, Mazumder S, Melo JS, Basak CB, Dasgupta K. Porous nano-structured micro-granules from silica-milk bi-colloidal suspension: Synthesis and characterization. Colloids Surf B Biointerfaces 2017; 154:421-428. [PMID: 28388528 DOI: 10.1016/j.colsurfb.2017.03.048] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Revised: 02/28/2017] [Accepted: 03/23/2017] [Indexed: 02/06/2023]
Abstract
Synthesis and characterization of nano-structured porous granules, with fairly defined morphology and porosity, is crucial because such granules are widely utilized for various technological applications. However, an easy, one-step, economic synthesis protocol for large scale production is extremely desirable. In the present work, we have reported the synthesis and characterization of the nano-structured micro-granules using aerosol drying of bi-colloidal suspension of nano-silica and milk. Removal of soft organic component from the granules results in formation of meso and macro pores with moderate specific surface area. Granule morphology and porosity depends strongly on the concentration ratio of the individual components in the drying aerosol as well as the interaction between them.
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Affiliation(s)
- Priyanka Biswas
- Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai, 400085, India; Homi Bhabha National Institute, Anushaktinagar, Mumbai, 400094, India
| | - D Sen
- Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai, 400085, India; Homi Bhabha National Institute, Anushaktinagar, Mumbai, 400094, India.
| | - S Mazumder
- Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai, 400085, India; Homi Bhabha National Institute, Anushaktinagar, Mumbai, 400094, India
| | - J S Melo
- Nuclear Agriculture & Biotechnology Division, Bhabha Atomic Research Centre, Mumbai, 400085, India; Homi Bhabha National Institute, Anushaktinagar, Mumbai, 400094, India
| | - C B Basak
- Glass and Advanced Materials Division, Bhabha Atomic Research Centre, Mumbai, 400085, India
| | - Kinshuk Dasgupta
- Materials Group, Bhabha Atomic Research Centre, Mumbai, 400085, India
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24
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Koshari SHS, Ross JL, Nayak PK, Zarraga IE, Rajagopal K, Wagner NJ, Lenhoff AM. Characterization of Protein–Excipient Microheterogeneity in Biopharmaceutical Solid-State Formulations by Confocal Fluorescence Microscopy. Mol Pharm 2017; 14:546-553. [DOI: 10.1021/acs.molpharmaceut.6b00940] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Stijn H. S. Koshari
- Center
for Molecular and Engineering Thermodynamics, Department of Chemical
and Biomolecular Engineering, University of Delaware, Newark, Delaware 19716, United States
| | - Jean L. Ross
- DBI
Bio-Imaging Center, Delaware Biotechnology Institute, Newark, Delaware 19711, United States
| | - Purnendu K. Nayak
- Eurofins Lancaster Laboratories Inc., Lancaster, Pennsylvania 17605, United States
| | - Isidro E. Zarraga
- Late
Stage Pharmaceutical Development, Genentech Inc., South San Francisco, California 94080, United States
| | - Karthikan Rajagopal
- Drug
Delivery Department, Genentech Inc., South San Francisco, California 94080, United States
| | - Norman J. Wagner
- Center
for Molecular and Engineering Thermodynamics, Department of Chemical
and Biomolecular Engineering, University of Delaware, Newark, Delaware 19716, United States
| | - Abraham M. Lenhoff
- Center
for Molecular and Engineering Thermodynamics, Department of Chemical
and Biomolecular Engineering, University of Delaware, Newark, Delaware 19716, United States
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25
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Basu S, Bansal L, Miglani A. Towards universal buckling dynamics in nanocolloidal sessile droplets: the effect of hydrophilic to superhydrophobic substrates and evaporation modes. SOFT MATTER 2016; 12:4896-4902. [PMID: 27125247 DOI: 10.1039/c6sm00837b] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The evaporation of a nanocolloidal sessile droplet exhibits preferential particle assembly, nanoporous shell formation and buckling to form cavities with unique morphological features. Here, we have established many universal trends that explain the buckling dynamics under one umbrella irrespective of hydrophobicity, evaporation mode and particle loading. We provide a regime map explaining the droplet morphology and buckling characteristics for droplet evaporation on various substrates. Specifically, we find that the final droplet volume and the radius of curvature at the buckling onset are universal functions of particle concentration. Furthermore, we establish that post-buckling cavity growth is evaporation driven regardless of the substrate.
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Affiliation(s)
- Saptarshi Basu
- Department of Mechanical Engineering, Indian Institute of Science, Bangalore, 560012, India.
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26
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Silica encapsulated lipid-based drug delivery systems for reducing the fed/fasted variations of ziprasidone in vitro. Eur J Pharm Biopharm 2016; 101:33-42. [DOI: 10.1016/j.ejpb.2016.01.010] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Revised: 01/14/2016] [Accepted: 01/18/2016] [Indexed: 12/23/2022]
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27
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Pathak B, Basu S. Modulation of Buckling Dynamics in Nanoparticle Laden Droplets Using External Heating. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:2591-2600. [PMID: 26938984 DOI: 10.1021/acs.langmuir.6b00544] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Dynamics of contact free (levitated) drying of nanofluid droplets is ubiquitous in many application domains ranging from spray drying to pharmaceutics. Controlling the final morphology (macro to micro scales) of the dried out sample poses some serious challenges. Evaporation of solvent and agglomeration of particles leads to porous shell formation in acoustically levitated nanosilica droplets. The capillary pressure due to evaporation across the menisci at the nanoscale pores causes buckling of the shell which leads to ring and bowl shaped final structures. Acoustics plays a crucial role in flattening of droplets which is a prerequisite for initiation of buckling in the shell. Introduction of mixed nanocolloids (sodium dodecyl sulfate + nanosilica) reduces evaporation rate, disrupts formation of porous shell, and enhances mechanical strength of the shell, all of which restricts the process of buckling. Although buckling is completely arrested in such surfactant added droplets, controlled external heating using laser enhances evaporation through the pores in the shell due to thermally induced structural changes and rearrangement of SDS aggregates which reinitializes buckling in such droplets. Furthermore, inclusion of anilinium hydrochloride into the nanoparticle laden droplets produces ions which adsorb and modify the morphology of sodium dodecyl sulfate crystals and reinitializes buckling in the shell (irrespective of external heating conditions). The kinetics of buckling is determined by the combined effect of morphology of the colloidal particles, particle/aggregate diffusion rate within the droplet, and the rate of evaporation of water. The buckling dynamics leads to cavity formation which grows subsequently to yield final structures with drastically different morphological features. The cavity growth is controlled by evaporation through the nanoscale pores and exhibits a universal trend irrespective of heating rate and nanoparticle type.
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Affiliation(s)
- Binita Pathak
- Department of Mechanical Engineering, Indian Institute of Science Bangalore , Bangalore, Karnataka - 560012, India
| | - Saptarshi Basu
- Department of Mechanical Engineering, Indian Institute of Science Bangalore , Bangalore, Karnataka - 560012, India
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28
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Biswas P, Sen D, Mazumder S, Basak CB, Doshi P. Temperature Mediated Morphological Transition during Drying of Spray Colloidal Droplets. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:2464-73. [PMID: 26900937 DOI: 10.1021/acs.langmuir.5b04171] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Understanding how a tiny dilute evaporative colloidal spray droplet gets transformed into a microgranule with a characteristic morphology is crucial from scientific as well as technological points of view. In the present work, it is demonstrated that the morphology and the size distribution of the microcapsules can be tuned simply by adjusting the drying temperature. Shape and size of the capsules are quantified at four different drying temperatures. It is shown that the morphology transits gradually from sphere to toroid with increasing temperature keeping the average volume-fraction of the correlated nanoparticles nearly unaffected for the synthesized granules. A plausible mechanism for the chronological pathway of such morphological transformation is illustrated. Computer simulation corroborates the experimentally observed morphological transition. The variation in hollowness and buckling tendency of the capsules are elucidated by scattering and imaging techniques.
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Affiliation(s)
| | - D Sen
- Homi Bhabha National Institute , Mumbai 400094, India
| | - S Mazumder
- Homi Bhabha National Institute , Mumbai 400094, India
| | | | - P Doshi
- Groton Laboratories, Pfizer Global Research and Development , Groton, 06340 Connecticut United States
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29
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Bansal L, Miglani A, Basu S. Universal buckling kinetics in drying nanoparticle-laden droplets on a hydrophobic substrate. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2015; 92:042304. [PMID: 26565237 DOI: 10.1103/physreve.92.042304] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Indexed: 06/05/2023]
Abstract
We provide a comprehensive physical description of the vaporization, self-assembly, agglomeration, and buckling kinetics of sessile nanofluid droplets pinned on a hydrophobic substrate. We have deciphered five distinct regimes of the droplet life cycle. Regimes I-III consists of evaporation-induced preferential agglomeration that leads to the formation of a unique dome-shaped inhomogeneous shell with a stratified varying-density liquid core. Regime IV involves capillary-pressure-initiated shell buckling and stress-induced shell rupture. Regime V marks rupture-induced cavity inception and growth. We demonstrate through scaling arguments that the growth of the cavity (which controls the final morphology or structure) can be described by a universal function.
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Affiliation(s)
- Lalit Bansal
- Department of Mechanical Engineering, Indian Institute of Science, Bangalore, India-560012
| | - Ankur Miglani
- Department of Mechanical Engineering, Indian Institute of Science, Bangalore, India-560012
| | - Saptarshi Basu
- Department of Mechanical Engineering, Indian Institute of Science, Bangalore, India-560012
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30
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Parviz D, Metzler SD, Das S, Irin F, Green MJ. Tailored Crumpling and Unfolding of Spray-Dried Pristine Graphene and Graphene Oxide Sheets. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2015; 11:2661-2668. [PMID: 25641827 DOI: 10.1002/smll.201403466] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Revised: 12/29/2014] [Indexed: 06/04/2023]
Abstract
For the first time, pristine graphene can be controllably crumpled and unfolded. The mechanism for graphene is radically different than that observed for graphene oxide; a multifaced crumpled, dimpled particle morphology is seen for pristine graphene in contrast to the wrinkled, compressed surface of graphene oxide particles, showing that surface chemistry dictates nanosheet interactions during the crumpling process. The process demonstrated here utilizes a spray-drying technique to produce droplets of aqueous graphene dispersions and induce crumpling through rapid droplet evaporation. For the first time, the gradual dimensional transition of 2D graphene nanosheets to a 3D crumpled morphology in droplets is directly observed; this is imaged by a novel sample collection device inside the spray dryer itself. The degree of folding can be tailored by altering the capillary forces on the dispersed sheets during evaporation. It is also shown that the morphology of redispersed crumpled graphene powder can be controlled by solvent selection. This process is scalable, with the ability to rapidly process graphene dispersions into powders suitable for a variety of engineering applications.
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Affiliation(s)
- Dorsa Parviz
- Department of Chemical Engineering, Texas Tech University, Lubbock, TX, 79409, USA
- Department of Chemical Engineering, Texas A&M University, College Station, TX, 77843, USA
| | - Shane D Metzler
- Department of Chemical Engineering, Texas Tech University, Lubbock, TX, 79409, USA
| | - Sriya Das
- Department of Chemical Engineering, Texas Tech University, Lubbock, TX, 79409, USA
| | - Fahmida Irin
- Department of Chemical Engineering, Texas Tech University, Lubbock, TX, 79409, USA
| | - Micah J Green
- Department of Chemical Engineering, Texas Tech University, Lubbock, TX, 79409, USA
- Department of Chemical Engineering, Texas A&M University, College Station, TX, 77843, USA
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31
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Bahadur J, Sen D, Mazumder S, Santoro G, Yu S, Roth SV, Melnichenko YB. Colloidal Nanoparticle Interaction Transition during Solvent Evaporation Investigated by in-Situ Small-Angle X-ray Scattering. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:4612-4618. [PMID: 25839830 DOI: 10.1021/la504769k] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
In-situ scanning small-angle X-ray scattering (SAXS) experiments have been performed to probe the drying of a single suspended droplet of silica colloids. It has been demonstrated that the formation of a nanoparticle shell during drying can be confirmed just by measuring the temporal evolution of the spatial transmission profile across the drying droplet. The shrinkage of the droplet stops once the shell is formed. The temporal dependence of the shell thickness and droplet radius has been estimated by quantitative analysis of the functionality of the transmission profiles. It is revealed that the position of the correlation peak originating from interactions between silica nanoparticles evolves linearly during the initial stage of drying and exhibits sigmoidal growth behavior in later stages. The interaction between colloidal particles in different drying stages has been investigated. We provide experimental confirmation of the transition from repulsive interaction to a capillary-driven short-range attraction during shell formation. The present work demonstrates that in-situ scanning SAXS on a suspended droplet is an invaluable technique for monitoring the dynamic self-organization of colloids as it probes the drying of complex fluids without the interference of a substrate.
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Affiliation(s)
- J Bahadur
- †Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400085, India
- ‡Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - D Sen
- †Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400085, India
| | - S Mazumder
- †Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400085, India
| | - G Santoro
- §Photon Science, Deutsches Elektronen-Synchrotron (DESY), Notkestr. 85 D-22607, Hamburg, Germany
| | - S Yu
- §Photon Science, Deutsches Elektronen-Synchrotron (DESY), Notkestr. 85 D-22607, Hamburg, Germany
| | - S V Roth
- §Photon Science, Deutsches Elektronen-Synchrotron (DESY), Notkestr. 85 D-22607, Hamburg, Germany
| | - Y B Melnichenko
- ‡Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
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32
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Miglani A, Basu S. Sphere to ring morphological transformation in drying nanofluid droplets in a contact-free environment. SOFT MATTER 2015; 11:2268-78. [PMID: 25652122 DOI: 10.1039/c4sm02553a] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Understanding the transients of buckling in drying colloidal suspensions is pivotal for producing new functional microstructures with tunable morphologies. Here, we report first observations and elucidate the buckling instability induced morphological transition (sphere to ring structure) in an acoustically levitated, heated nanosuspension droplet using dynamic energy balance. Droplet deformation featuring the formation of symmetric cavities is initiated by capillary pressure that is two to three orders of magnitude greater than the acoustic radiation pressure, thus indicating that the standing pressure field has no influence on the buckling front kinetics. With an increase in heat flux, the growth rate of surface cavities and their post-buckled volume increase while the buckling time period reduces, thereby altering the buckling pathway and resulting in distinct precipitate structures. However, irrespective of the heating rate, the volumetric droplet deformation exhibits a linear time dependence and the droplet vaporization is observed to deviate from the classical D(2)-law.
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Affiliation(s)
- Ankur Miglani
- Department of Mechanical Engineering, Indian Institute of Science, Bangalore, Karnataka-560012, India.
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E. coli imprinted nano-structured silica micro-granules by spray drying: Optimization of calcination temperature. Colloids Surf B Biointerfaces 2015; 127:164-71. [DOI: 10.1016/j.colsurfb.2015.01.031] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Revised: 12/08/2014] [Accepted: 01/20/2015] [Indexed: 11/22/2022]
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Sen D, Lakhotiya H, Das A, Bahadur J, Mazumder S, Basak CB. Organic–inorganic composite micro-granules by evaporation induced assembly: role of trapped water in structural evolution. RSC Adv 2015. [DOI: 10.1039/c4ra14703k] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Nano-structured composite micro-granules are promising candidates for many technological and medical applications.
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Affiliation(s)
- D. Sen
- Solid State Physics Division
- Bhabha Atomic Research Centre
- Mumbai-400085
- India
| | - H. Lakhotiya
- Solid State Physics Division
- Bhabha Atomic Research Centre
- Mumbai-400085
- India
- Centre for Converging Technologies
| | - Avik Das
- Solid State Physics Division
- Bhabha Atomic Research Centre
- Mumbai-400085
- India
| | - J. Bahadur
- Solid State Physics Division
- Bhabha Atomic Research Centre
- Mumbai-400085
- India
| | - S. Mazumder
- Solid State Physics Division
- Bhabha Atomic Research Centre
- Mumbai-400085
- India
| | - C. B. Basak
- Glass and Advanced Materials Division
- Bhabha Atomic Research Centre
- Mumbai-400085
- India
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Tan A, Colliat-Dangus P, Whitby CP, Prestidge CA. Controlling the enzymatic digestion of lipids using hybrid nanostructured materials. ACS APPLIED MATERIALS & INTERFACES 2014; 6:15363-71. [PMID: 25116477 DOI: 10.1021/am5038577] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Solid nanoparticle-lipid hybrids have been engineered by using spray drying to assemble monodisperse hydrophilic silica nanoparticles and submicron lipid (triglyceride) emulsions together into composite microparticles, which have specific activity toward enzymes. The influence of silica particle size (100-1000 nm) and emulsifier type (anionic and cationic) on the three-dimensional structure of the composite particles was investigated. The nanostructure of the hybrid particles, which is controlled by the size of the voids between the closely packed silica particles, plays a critical role in lipase action and hence lipid digestion kinetics. Confining lipid droplets within the nanostructured silica aggregates led to 2- to 15-fold enhanced rate of lipolysis in comparison with dispersed coarse oil droplets. The composite particles were tailored to enhance, retain or sustain the lipolysis kinetics of submicron lipid emulsions. The presence of repulsive nanoparticle-droplet interactions favored aqueous redispersion and fast lipolysis of the hybrid composite materials, while attractive interactions hindered redispersion and delayed lipolysis of the confined lipid droplets. Such hybrid nanomaterials can be exploited to control the gastrointestinal enzymatic action and promisingly form the basis for the next generation of foods and medicines.
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Affiliation(s)
- Angel Tan
- Ian Wark Research Institute, University of South Australia , Mawson Lakes Campus, Mawson Lakes, SA 5095, Australia
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Giovagnoli S, Palazzo F, Michele AD, Schoubben A, Blasi P, Ricci M. The Influence of Feedstock and Process Variables on the Encapsulation of Drug Suspensions by Spray‐Drying in Fast Drying Regime: The Case of Novel Antitubercular Drug–Palladium Complex Containing Polymeric Microparticles. J Pharm Sci 2014; 103:1255-68. [DOI: 10.1002/jps.23902] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Sen D, Bahadur J, Mazumder S, Santoro G, Yu S, Roth SV. Probing evaporation induced assembly across a drying colloidal droplet using in situ small-angle X-ray scattering at the synchrotron source. SOFT MATTER 2014; 10:1621-1627. [PMID: 24651879 DOI: 10.1039/c3sm52039k] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Colloidal particles in a tiny drying droplet are forced to assemble due to attractive capillary forces. Jamming of the particles throughout the droplet remains either isotropic or anisotropic depending upon the drying kinetics and the physicochemical environment. In this work, we explore the dynamical evolution of such an assembly process across a single evaporative droplet by in situ scanning small-angle scattering using a micro-focused X-ray beam at the synchrotron source. A methodology has been elucidated to differentiate quantitatively between the isotropic and the anisotropic jamming process. Switching of jamming behaviour depending on the initial particle volume fraction in the droplet has been demonstrated. Three distinct stages of assembly, associated with droplet shrinkage, have been revealed even during isotropic jamming. This is in contrast to the drying of a pure liquid droplet under diffusion limited evaporation. It has been established that such in situ scattering measurements can also be used to estimate the temporal evolutions of the viscosity of a drying suspension as well as the diffusivity of nanoparticles in a droplet.
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Affiliation(s)
- D Sen
- Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai-400085, India.
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Sen D, Ghosh A, Mazumder S, Bindal R, Tewari P. Novel polysulfone–spray-dried silica composite membrane for water purification: Preparation, characterization and performance evaluation. Sep Purif Technol 2014. [DOI: 10.1016/j.seppur.2013.12.019] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Bahadur J, Prakash J, Sen D, Mazumder S, Sastry PU, Paul B, Chakravartty JK, Lemmel H. A facile fabrication of a uniform and homogeneous CNT–TiO2 composite: a microscopic and scattering investigation. RSC Adv 2014. [DOI: 10.1039/c4ra00619d] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Mechanism for formation of TiO2 submicrospheres via spray-hydrolysis of micrometric aqueous droplets; hydrolysis reaction occurs at the water–hexane interface.
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Affiliation(s)
- J. Bahadur
- Solid State Physics Division
- Bhabha Atomic Research Centre
- Mumbai, India
| | - J. Prakash
- Powder Metallurgy Division
- Bhabha Atomic Research Centre
- Mumbai, India
| | - D. Sen
- Solid State Physics Division
- Bhabha Atomic Research Centre
- Mumbai, India
| | - S. Mazumder
- Solid State Physics Division
- Bhabha Atomic Research Centre
- Mumbai, India
| | - P. U. Sastry
- Solid State Physics Division
- Bhabha Atomic Research Centre
- Mumbai, India
| | - B. Paul
- Materials Processing Division Bhabha Atomic Research Centre
- Mumbai, India
| | | | - H. Lemmel
- Institut Laue-Langevin
- Grenoble Cedex 9, France
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Herzog G, Benecke G, Buffet A, Heidmann B, Perlich J, Risch JFH, Santoro G, Schwartzkopf M, Yu S, Wurth W, Roth SV. In situ grazing incidence small-angle X-ray scattering investigation of polystyrene nanoparticle spray deposition onto silicon. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:11260-11266. [PMID: 23927828 DOI: 10.1021/la402254q] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
We investigated the spray deposition and subsequent self-assembly during drying of a polystyrene nanoparticle dispersion with in situ grazing incidence small-angle X-ray scattering at high time resolution. During the fast deposition of the dispersion and the subsequent evaporation of the solvent, different transient stages of nanoparticle assembly can be identified. In the first stage, the solvent starts to evaporate without ordering of the nanoparticles. During the second stage, large-scale structures imposed by the breakup of the liquid film are observable. In this stage, the solvent evaporates further and nanoparticle ordering starts. In the late third drying stage, the nanoparticles self-assemble into the final layer structure.
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Affiliation(s)
- Gerd Herzog
- Deutsches Elektronen-Synchrotron (DESY) , Notkestrasse 85, D-22607 Hamburg, Germany
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Fang A, Gosse C, Gaillard C, Zhao X, Davy J. Tuning silica particle shape at fluid interfaces. LAB ON A CHIP 2012; 12:4960-3. [PMID: 23051755 DOI: 10.1039/c2lc40852j] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
By exploring the phenomenon of water diffusion induced self-assembly of silica particle in microfluidic channels, we show that both the geometric confinement experienced by the droplet and the local Peclet number are responsible for the final particle shape. This study will facilitate the understanding and ultimately control of self assembly at fluid interfaces.
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Affiliation(s)
- Aiping Fang
- NANO, UR 1268, BIA, INRA, rue de la Géraudière, 44316 Nantes, France.
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Bahadur J, Sen D, Mazumder S, Sastry PU, Paul B, Bhatt H, Singh SG. One-step fabrication of thermally stable TiO2/SiO2 nanocomposite microspheres by evaporation-induced self-assembly. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:11343-11353. [PMID: 22794199 DOI: 10.1021/la3022886] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The evaporation-induced self-assembly of mixed colloids has been employed to synthesize microspheres of TiO(2)/SiO(2) nanocomposites. Small-angle neutron/X-ray scattering and scanning electron microscopy experiments reveal the hierarchical morphology of the microspheres. Although the internal structure of the microspheres, consisting of solely silica nanoparticles, gets significantly modified with time because of the reduction in the high specific surface area by internal coalescence, the same for the composite microspheres remains stable over an aging time of 1 year. Such temporal stability of the composite microspheres is attributed to the inhibition of coalescence of the silica nanoparticles in the presence of titania nanoparticles. X-ray diffraction and thermogravimetric results show the improved thermal stability of the composite grains against the anatase-to-rutile phase transition. Such thermal stability is attributed to the suppression of the growth of titania nanoparticles in the presence of silica nanoparticles. The UV-vis results indicate the confinement effect of the TiO(2) nanoparticles in the silica matrix. A plausible mechanism has been elucidated for the formation of microspheres with different morphology during self-assembly.
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Affiliation(s)
- J Bahadur
- Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400085, India.
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Bahadur J, Sen D, Mazumder S, Paul B, Bhatt H, Singh SG. Control of buckling in colloidal droplets during evaporation-induced assembly of nanoparticles. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:1914-1923. [PMID: 22185181 DOI: 10.1021/la204161d] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Micrometric grains of anisotropic morphology have been achieved by evaporation-induced self-assembly of silica nanoparticles. The roles of polymer concentration and its molecular weight in controlling the buckling behavior of drying droplets during assembly have been investigated. Buckled doughnut grains have been observed in the case of only silica colloid. Such buckling of the drying droplet could be arrested by attaching poly(ethylene glycol) on the silica surface. The nature of buckling in the case of only silica as well as modified silica colloids has been explained in terms of theory of homogeneous elastic shell under capillary pressure. However, it has been observed that colloids, modified by polymer with relatively large molecular weight, gives rise to buckyball-type grains at higher concentration and could not be explained by the above theory. It has been demonstrated that the shell formed during drying of colloidal droplet in the presence of polymer becomes inhomogeneous due to the presence of soft polymer rich zones on the shell that act as buckling centers, resulting in buckyball-type grains.
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Affiliation(s)
- J Bahadur
- Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai-400085, India.
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