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Polanowski P, Jeszka JK, Matyjaszewski K. Crosslinking and Gelation of Polymer Brushes and Free Polymer Chains in a Confined Space during Controlled Radical Polymerization─A Computer Simulation Study. Macromolecules 2023. [DOI: 10.1021/acs.macromol.2c02342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/30/2023]
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2
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The Influence of Constraints on Gelation in a Controlling/Living Copolymerization Process. Int J Mol Sci 2023; 24:ijms24032701. [PMID: 36769024 PMCID: PMC9916906 DOI: 10.3390/ijms24032701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 01/24/2023] [Accepted: 01/28/2023] [Indexed: 02/04/2023] Open
Abstract
We developed a simple model of the copolymerization process in the formation of crosslinked macromolecular systems. A living copolymerization was carried out for free chains, in bulk and in a slit, as well as for grafted chains in a slit. In addition, polymer 2D brushes were placed in a slit with initiator molecules attached to one of the confining walls. Coarse-grained chains were embedded in the vertices of a face-centered cubic lattice with the excluded volume interactions. The simulations of the copolymerization processes were performed using the Dynamic Lattice Liquid algorithm, a version of the Monte Carlo method. The influence of the initial initiator to cross-linker ratio, slit width and grafting on the polymerization and on the gelation was examined. It was also shown that the influence of a confining slit was rather small, while the grafting of chains affected the location of the gel pint significantly.
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3
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Liu Y, Wu Y, Zhou F. Shear-Stable Polymer Brush Surfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:37-44. [PMID: 36546609 DOI: 10.1021/acs.langmuir.2c03012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Research on polymer brushes (PBs) has aroused great interest due to their wide range of applications in lubrication, antifogging, antifouling, self-cleaning, antiadhesion, antibacterial effects, and so forth. However, the weak mechanical strength, especially the low bond strength between the PBs and the substrate surface, is a long-standing challenge for its practical applications, which is directly related to the service life of the PB surface. Fortunately, the imperfection of the PB surface was gradually solved by researchers by combining the action of the chemical and physical anchoring strength, and many shear-stable PB surfaces were developed. In this Perspective, we present recent developments in the studies of shear-stable PBs. Conventional strategies that altered the structure of PB chain methods, including increasing grafted density, cross-linking of PBs, cyclic PBs, and so forth, are introduced briefly. The systematic subsurface grafting of the polymer brush (SSPB) strategy was introduced emphatically. The SSPB method grafted PB into the subsurface with considerable depth and gave a robust and reusable PB layer, which provided an approach for tackling the shear-resistance issue. Besides, the robust hydrophobic poly(dimethylsiloxane) (PDMS) brush surface that lubricated itself in air was also introduced. Finally, we provide a synopsis and discuss the outlook of the shear-stable PB surface.
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Affiliation(s)
- Yizhe Liu
- State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Gansu, Lanzhou 730000, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yang Wu
- State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Gansu, Lanzhou 730000, China
- Yantai Zhongke Research Institute of Advanced Materials and Green Chemical Engineering, Shandong Laboratory of Advanced Materials and Green Manufacturing, Yantai 264006, China
- Qingdao Centre of Resource Chemistry and New Materials, Shandong Qingdao 266100, China
| | - Feng Zhou
- State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Gansu, Lanzhou 730000, China
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Chau AL, Getty PT, Rhode AR, Bates CM, Hawker CJ, Pitenis AA. Superlubricity of pH-responsive hydrogels in extreme environments. Front Chem 2022; 10:891519. [PMID: 36034669 PMCID: PMC9405656 DOI: 10.3389/fchem.2022.891519] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Accepted: 06/28/2022] [Indexed: 11/13/2022] Open
Abstract
Poly(acrylamide-co-acrylic acid) (P(AAm-co-AA)) hydrogels are highly tunable and pH-responsive materials frequently used in biomedical applications. The swelling behavior and mechanical properties of these gels have been extensively characterized and are thought to be controlled by the protonation state of the acrylic acid (AA) through the regulation of solution pH. However, their tribological properties have been underexplored. Here, we hypothesized that electrostatics and the protonation state of AA would drive the tribological properties of these polyelectrolyte gels. P(AAm-co-AA) hydrogels were prepared with constant acrylamide (AAm) concentration (33 wt%) and varying AA concentration to control the amount of ionizable groups in the gel. The monomer:crosslinker molar ratio (200:1) was kept constant. Hydrogel swelling, stiffness, and friction behavior were studied by systematically varying the acrylic acid (AA) concentration from 0-12 wt% and controlling solution pH (0.35, 7, 13.8) and ionic strength (I = 0 or 0.25 M). The stiffness and friction coefficient of bulk hydrogels were evaluated using a microtribometer and borosilicate glass probes as countersurfaces. The swelling behavior and elastic modulus of these polyelectrolyte hydrogels were highly sensitive to solution pH and poorly predicted the friction coefficient (µ), which decreased with increasing AA concentration. P(AAm-co-AA) hydrogels with the greatest AA concentrations (12 wt%) exhibited superlubricity (µ = 0.005 ± 0.001) when swollen in unbuffered, deionized water (pH = 7, I = 0 M) and 0.5 M NaOH (pH = 13.8, I = 0.25 M) (µ = 0.005 ± 0.002). Friction coefficients generally decreased with increasing AA and increasing solution pH. We postulate that tunable lubricity in P(AAm-co-AA) gels arises from changes in the protonation state of acrylic acid and electrostatic interactions between the probe and hydrogel surface.
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Affiliation(s)
- Allison L. Chau
- Materials Department, University of California, Santa Barbara, Santa Barbara, CA, United States
| | - Patrick T. Getty
- Materials Department, University of California, Santa Barbara, Santa Barbara, CA, United States
| | - Andrew R. Rhode
- Materials Department, University of California, Santa Barbara, Santa Barbara, CA, United States
| | - Christopher M. Bates
- Materials Department, University of California, Santa Barbara, Santa Barbara, CA, United States
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, CA, United States
| | - Craig J. Hawker
- Materials Department, University of California, Santa Barbara, Santa Barbara, CA, United States
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, CA, United States
| | - Angela A. Pitenis
- Materials Department, University of California, Santa Barbara, Santa Barbara, CA, United States
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Yin X, Wu D, Yang H, Wang J, Zhang X, Li H, Zheng T, Wang L, Zhang T. Galvanic-Replacement-Assisted Surface-Initiated Atom Transfer Radical Polymerization for Functional Polymer Brush Engineering. ACS Macro Lett 2022; 11:296-302. [PMID: 35575363 DOI: 10.1021/acsmacrolett.1c00781] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Here we present a facile and robust strategy, namely, galvanic-replacement-assisted surface-initiated Cu(0)-mediated atom transfer radical polymerization (gr-SI-Cu0ATRP, or gr-SI-Cu0CRP) for polymer brush engineering under ambient conditions. In gr-SI-Cu0ATRP, highly active and nanostructured Cu(0) surfaces are obtained by a simple galvanic replacement on zinc/aluminum surfaces in dilute Cu2+ solution. Polymer brush growth rate is extremely high (up to ∼904 nm in 30 min polymerization); meanwhile, both nano Cu(0) surfaces and Cu2+ solution can be reused multiple times without losing grafting efficiency. We also demonstrate that the gr-SI-Cu0ATRP is advantageous for polymer brush engineering on arbitrary substrates, including flexible (polyethylene terephthalate), curved (polycarbonate), and porous (anodic aluminum oxide), and endow the substrates with various functionalities, for example, anti-icing, antifogging, and ion selectivity.
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Affiliation(s)
- Xiaodong Yin
- Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
- University of Chinese Academy of Sciences, 19A Yuquan Road, Beijing 100049, China
| | - Daheng Wu
- Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
| | - Haoyong Yang
- Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
- University of Chinese Academy of Sciences, 19A Yuquan Road, Beijing 100049, China
| | - Jianing Wang
- Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
| | - Xiaoxuan Zhang
- Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
| | - He Li
- Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
| | - Tianyue Zheng
- Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
| | - Liping Wang
- Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
- University of Chinese Academy of Sciences, 19A Yuquan Road, Beijing 100049, China
| | - Tao Zhang
- Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
- University of Chinese Academy of Sciences, 19A Yuquan Road, Beijing 100049, China
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Li H, Zhang Y, Jones S, Segalman R, Warr GG, Atkin R. Interfacial nanostructure and friction of a polymeric ionic liquid-ionic liquid mixture as a function of potential at Au(111) electrode interface. J Colloid Interface Sci 2022; 606:1170-1178. [PMID: 34487936 DOI: 10.1016/j.jcis.2021.08.067] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 08/09/2021] [Accepted: 08/09/2021] [Indexed: 11/28/2022]
Abstract
HYPOTHESIS The polymeric cations of polymeric ionic liquids (PILs) can adsorb from the bulk of a conventional ionic liquid (IL) to the Au(111) electrode interface and form a boundary layer. The interfacial properties of the PIL boundary layer may be tuned by potential. EXPERIMENTS Atomic force microscopy has been used to investigate the changes of surface morphology, normal and lateral forces of a 5 wt% PIL/IL mixture as a function of potential. FINDINGS Polymeric cations adsorb strongly to Au(111) and form a polymeric cation-enriched boundary layer at -1.0 V. This boundary layer binds less strongly to the surface at open circuit potential (OCP) and weakly at + 1.0 V. The polymeric cation chains are compressed at -1.0 V and OCP owing to electrical attractions with the electrode surface, but fully stretched at + 1.0 V due to electrical repulsions. The lateral forces of the 5 wt% PIL/IL mixture at -1.0 V and OCP are higher than at + 1.0 V as the polymeric cation-enriched boundary layer is rougher and has stronger interactions with the AFM probe; at + 1.0 V, the lateral force is low and comparable to pure conventional IL due to displacement of polymeric cations with conventional anions in the boundary layer.
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Affiliation(s)
- Hua Li
- School of Molecular Sciences, The University of Western Australia, Perth, Western Australia, Australia; Centre for Microscopy, Characterisation and Analysis, The University of Western Australia, Perth, Western Australia, Australia.
| | - Yunxiao Zhang
- School of Molecular Sciences, The University of Western Australia, Perth, Western Australia, Australia
| | - Seamus Jones
- Department of Chemical Engineering and Materials Department, University of California, Santa Barbara, Santa Barbara, CA 93106, United States
| | - Rachel Segalman
- Department of Chemical Engineering and Materials Department, University of California, Santa Barbara, Santa Barbara, CA 93106, United States
| | - Gregory G Warr
- School of Chemistry and Sydney Nano Institute, The University of Sydney, NSW 2006, Australia
| | - Rob Atkin
- School of Molecular Sciences, The University of Western Australia, Perth, Western Australia, Australia.
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Oevreeide IH, Szydlak R, Luty M, Ahmed H, Prot V, Skallerud BH, Zemła J, Lekka M, Stokke BT. On the Determination of Mechanical Properties of Aqueous Microgels-Towards High-Throughput Characterization. Gels 2021; 7:64. [PMID: 34072792 PMCID: PMC8261632 DOI: 10.3390/gels7020064] [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: 04/23/2021] [Revised: 05/21/2021] [Accepted: 05/25/2021] [Indexed: 12/15/2022] Open
Abstract
Aqueous microgels are distinct entities of soft matter with mechanical signatures that can be different from their macroscopic counterparts due to confinement effects in the preparation, inherently made to consist of more than one domain (Janus particles) or further processing by coating and change in the extent of crosslinking of the core. Motivated by the importance of the mechanical properties of such microgels from a fundamental point, but also related to numerous applications, we provide a perspective on the experimental strategies currently available and emerging tools being explored. Albeit all techniques in principle exploit enforcing stress and observing strain, the realization differs from directly, as, e.g., by atomic force microscope, to less evident in a fluid field combined with imaging by a high-speed camera in high-throughput strategies. Moreover, the accompanying analysis strategies also reflect such differences, and the level of detail that would be preferred for a comprehensive understanding of the microgel mechanical properties are not always implemented. Overall, the perspective is that current technologies have the capacity to provide detailed, nanoscopic mechanical characterization of microgels over an extended size range, to the high-throughput approaches providing distributions over the mechanical signatures, a feature not readily accessible by atomic force microscopy and micropipette aspiration.
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Affiliation(s)
- Ingrid Haga Oevreeide
- Biophysics and Medical Technology, Department of Physics, NTNU The Norwegian University of Science and Technology, NO-7491 Trondheim, Norway; (I.H.O.); (H.A.)
| | - Renata Szydlak
- Institute of Nuclear Physics, Polish Academy of Sciences, PL-31342 Krakow, Poland; (R.S.); (M.L.); (J.Z.)
| | - Marcin Luty
- Institute of Nuclear Physics, Polish Academy of Sciences, PL-31342 Krakow, Poland; (R.S.); (M.L.); (J.Z.)
| | - Husnain Ahmed
- Biophysics and Medical Technology, Department of Physics, NTNU The Norwegian University of Science and Technology, NO-7491 Trondheim, Norway; (I.H.O.); (H.A.)
| | - Victorien Prot
- Biomechanics, Department of Structural Engineering, NTNU The Norwegian University of Science and Technology, NO-7491 Trondheim, Norway; (V.P.); (B.H.S.)
| | - Bjørn Helge Skallerud
- Biomechanics, Department of Structural Engineering, NTNU The Norwegian University of Science and Technology, NO-7491 Trondheim, Norway; (V.P.); (B.H.S.)
| | - Joanna Zemła
- Institute of Nuclear Physics, Polish Academy of Sciences, PL-31342 Krakow, Poland; (R.S.); (M.L.); (J.Z.)
| | - Małgorzata Lekka
- Institute of Nuclear Physics, Polish Academy of Sciences, PL-31342 Krakow, Poland; (R.S.); (M.L.); (J.Z.)
| | - Bjørn Torger Stokke
- Biophysics and Medical Technology, Department of Physics, NTNU The Norwegian University of Science and Technology, NO-7491 Trondheim, Norway; (I.H.O.); (H.A.)
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Adibnia V, Ma Y, Halimi I, Walker GC, Banquy X, Kumacheva E. Phytoglycogen Nanoparticles: Nature-Derived Superlubricants. ACS NANO 2021; 15:8953-8964. [PMID: 33960783 DOI: 10.1021/acsnano.1c01755] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Phytoglycogen nanoparticles (PhG NPs), a single-molecule highly branched polysaccharide, exhibit excellent water retention, due to the abundance of close-packed hydroxyl groups forming hydrogen bonds with water. Here we report lubrication properties of close-packed adsorbed monolayers of PhG NPs acting as boundary lubricants. Using direct surface force measurements, we show that the hydrated nature of the NP layer results in its striking lubrication performance, with two distinct confinement-controlled friction coefficients. In the weak- to moderate-confinement regime, when the NP layer is compressed down to 8% of its original thickness under a normal pressure of up to 2.4 MPa, the NPs lubricate the surface with a friction coefficient of 10-3. In the strong-confinement regime, with 6.5% of the original layer thickness under a normal pressure of up to 8.1 MPa, the friction coefficient was 10-2. Analysis of the water content and energy dissipation in the confined NP film reveals that the lubrication is governed by synergistic contributions of unbound and bound water molecules, with the former contributing to lubrication properties in the weak- to moderate-confinement regime and the latter being responsible for the lubrication in the strong-confinement regime. These results unravel mechanistic insights that are essential for the design of lubricating systems based on strongly hydrated NPs.
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Affiliation(s)
- Vahid Adibnia
- Department of Chemistry, University of Toronto, Toronto, Ontario, Canada, M5S 3H6
- Faculty of Pharmacy, Université de Montréal, Montreal, Quebec, Canada, H3C 3J7
| | - Yingshan Ma
- Department of Chemistry, University of Toronto, Toronto, Ontario, Canada, M5S 3H6
| | - Ilias Halimi
- Department of Chemistry, University of Toronto, Toronto, Ontario, Canada, M5S 3H6
| | - Gilbert C Walker
- Department of Chemistry, University of Toronto, Toronto, Ontario, Canada, M5S 3H6
| | - Xavier Banquy
- Faculty of Pharmacy, Université de Montréal, Montreal, Quebec, Canada, H3C 3J7
| | - Eugenia Kumacheva
- Department of Chemistry, University of Toronto, Toronto, Ontario, Canada, M5S 3H6
- Institute of Biomedical Engineering, University of Toronto, Toronto, Canada, M5S 3G9
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Canada, M5S 3E5
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Thiele S, Andersson J, Dahlin A, Hailes RLN. Tuning the Thermoresponsive Behavior of Surface-Attached PNIPAM Networks: Varying the Crosslinker Content in SI-ATRP. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:3391-3398. [PMID: 33719454 PMCID: PMC8041372 DOI: 10.1021/acs.langmuir.0c03545] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 02/24/2021] [Indexed: 06/12/2023]
Abstract
The synthesis and thermoresponsive properties of surface-attached poly(N-isopropylacrylamide)-co-N,N'-methylene bisacrylamide (PNIPAM-co-MBAM) networks are investigated. The networks are formed via SI-ARGET-ATRP ("grafting-from") on thiol-based initiator-functionalized gold films. This method is reliable, well controlled, fast, and applicable to patterned surfaces (e.g., nanopores) for networks with dry thicknesses >20 nm. Surface-attached PNIPAM-co-MBAM gels are swollen below their volume phase transition temperature but above collapse without complete expulsion of water (retain ∼50 vol %). The swelling/collapse transition is studied using complementary SPR and QCMD techniques. The ratio between swollen and collapsed heights characterizes the thermoresponsive behavior and is shown to not depend on network height but to vary with MBAM content. The higher the proportion of the crosslinker, the lower the magnitude of the phase transition, until all responsiveness is lost at 5 mol % MBAM. The temperature range of the transition is broadened for more crosslinked PNIPAM-co-MBAM gels but remains centered around 32 °C. Upon reswelling, less crosslinked networks display sharp transitions, while for those containing ≥3 mol % MBAM, transitions remain broad. This tunable behavior persists for gels on nanostructured gold surfaces. Investigating PNIPAM-co-MBAM networks on gold plasmonic nanowell arrays is a starting point for expanding their scope as thermo-controlled nanoactuators.
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Trachsel L, Ramakrishna SN, Romio M, Spencer ND, Benetti EM. Topology and Molecular Architecture of Polyelectrolytes Determine Their pH-Responsiveness When Assembled on Surfaces. ACS Macro Lett 2021; 10:90-97. [PMID: 35548981 DOI: 10.1021/acsmacrolett.0c00750] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Polymer composition and topology of surface-grafted polyacids determine the amplitude of their pH-induced swelling transition. The intrinsic steric constraints characterizing cyclic poly(2-carboxypropyl-2-oxazoline) (c-PCPOXA) and poly(2-carboxyethyl-2-oxazoline) (c-PCEOXA) forming brushes on Au surfaces induce an enhancement in repulsive interactions between charged polymer segments upon deprotonation, leading to an amplified expansion and a significant increment in swelling with respect to their linear analogues of similar molar mass. On the other hand, it is the composition of polyacid grafts that governs their hydration in both undissociated and ionized forms, determining the degree of swelling during their pH-induced transition.
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Affiliation(s)
- Lucca Trachsel
- Tissue Engineering + Biofabrication Laboratory, Department of Health Sciences and Technology, ETH Zürich, 8093 Zürich, Switzerland
| | - Shivaprakash N. Ramakrishna
- Laboratory for Soft Materials and Interfaces, Department of Materials, ETH Zürich, Vladimir-Prelog-Weg 5, 8093 Zürich, Switzerland
| | - Matteo Romio
- Laboratory for Surface Science and Technology, Department of Materials, ETH Zürich, Vladimir-Prelog-Weg 5, 8093 Zürich, Switzerland
- Biointerfaces, Swiss Federal Laboratories for Materials Science and Technology (EMPA), Lerchenfeldstrasse 5, CH-9014, St. Gallen, Switzerland
| | - Nicholas D. Spencer
- Laboratory for Surface Science and Technology, Department of Materials, ETH Zürich, Vladimir-Prelog-Weg 5, 8093 Zürich, Switzerland
| | - Edmondo M. Benetti
- Laboratory for Surface Science and Technology, Department of Materials, ETH Zürich, Vladimir-Prelog-Weg 5, 8093 Zürich, Switzerland
- Biointerfaces, Swiss Federal Laboratories for Materials Science and Technology (EMPA), Lerchenfeldstrasse 5, CH-9014, St. Gallen, Switzerland
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11
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12
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Sim XM, Wang CG, Liu X, Goto A. Multistimuli Responsive Reversible Cross-Linking-Decross-Linking of Concentrated Polymer Brushes. ACS APPLIED MATERIALS & INTERFACES 2020; 12:28711-28719. [PMID: 32515964 DOI: 10.1021/acsami.0c07508] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Poly(furfuryl methacrylate) (PFMA) brushes were cross-linked using bismaleimide cross-linkers via the Diels-Alder (DA) reaction at 70 °C, generating cross-linked PFMA brushes (PFMA brush gels). The cross-linked PFMA brushes were decross-linked at 110 °C via the retro-Diels-Alder (rDA) reaction, offering the temperature-responsive reversible PFMA brush gels. The wettability of the brush was tunable by cross-linking and decross-linking. The use of a disulfide containing bismaleimide as a cross-linker gave the S-S bond at the cross-linking point. The S-S bond was cleaved upon thermal or photo stimulus and regenerated through oxidative stimulus, offering another reversible decross-linking/cross-linking pathway of the PFMA brush gel. The use of photo stimulus together with photomasks further offered patterned brushes with the cross-linked and decross-linked domains. The combination of the DA/rDA reactions and the reversible S-S bond cleavage provided multistimuli-responsive brush gels for switching the surface properties in unique manners. The reversible cross-linking, multiresponsiveness, access to patterned structures, and metal-free synthetic procedure are attractive features in the present approach for creating smart functional surfaces.
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Affiliation(s)
- Xuan Ming Sim
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, 637371 Singapore
| | - Chen-Gang Wang
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, 637371 Singapore
| | - Xu Liu
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, 637371 Singapore
| | - Atsushi Goto
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, 637371 Singapore
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13
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Igata K, Sakamaki T, Inutsuka Y, Higaki Y, Okajima MK, Yamada NL, Kaneko T, Takahara A. Cationic Polymer Brush/Giant Polysaccharide Sacran Assembly: Structure and Lubricity. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:6494-6501. [PMID: 32393028 DOI: 10.1021/acs.langmuir.0c00854] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
A highly effective aqueous lubrication strategy employing electrostatic assembly of a negatively charged ultrahigh molecular weight natural polysaccharide named "sacran" and a positively charged poly[2-(methacryloyloxy)ethyltrimethylammonium chloride] (PMTAC) brush was investigated. The PMTAC brush was compressed through the adsorption of sacran to produce the layered structure of a PMTAC brush/sacran hybrid bottom layer and a poorly hydrated sacran top layer. The dynamic friction coefficients of the PMTAC brush were drastically reduced in salt-free sacran aqueous solutions, and the lubrication mode transition from the brush-lubrication regime to hydrodynamic lubrication was promoted. The electrostatic assembly was inhibited by the addition of NaCl into the lubricant solutions, leading to the loss of the lubrication effect. The hydrodynamic lubrication would be encouraged by the local viscosity enhancement at the friction boundary due to the poorly hydrated and highly viscous PMTAC brush/sacran hybrid film produced by the spontaneous electrostatic assembly.
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Affiliation(s)
- Kosuke Igata
- Graduate School of Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Tatsunori Sakamaki
- Graduate School of Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Yoshihiro Inutsuka
- Graduate School of Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Yuji Higaki
- Department of Integrated Science and Technology, Faculty of Science and Technology, Oita University, 700 Dannoharu, Oita 870-1192, Japan
| | - Maiko K Okajima
- Japan Advanced Institute of Science and Technology (JAIST), 1-1 Asahidai, Nomi-shi, Ishikawa 923-1292, Japan
| | - Norifumi L Yamada
- Neutron Science Laboratory, High Energy Accelerator Research Organization, Ibaraki 319-1106, Japan
| | - Tatsuo Kaneko
- Japan Advanced Institute of Science and Technology (JAIST), 1-1 Asahidai, Nomi-shi, Ishikawa 923-1292, Japan
| | - Atsushi Takahara
- Graduate School of Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
- Institute for Materials Chemistry and Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
- International Institute for Carbon-Neutral Energy Research (WPI-I2CNER), Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
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14
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Adibnia V, Mirbagheri M, Salimi S, De Crescenzo G, Banquy X. Nonspecific interactions in biomedical applications. Curr Opin Colloid Interface Sci 2020. [DOI: 10.1016/j.cocis.2019.12.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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15
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Li H, Choi YS, Rutland MW, Atkin R. Nanotribology of hydrogels with similar stiffness but different polymer and crosslinker concentrations. J Colloid Interface Sci 2020; 563:347-353. [PMID: 31887698 DOI: 10.1016/j.jcis.2019.12.045] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Revised: 12/02/2019] [Accepted: 12/12/2019] [Indexed: 11/26/2022]
Abstract
HYPOTHESIS The stiffness has been found to regulate hydrogel performances and applications. However, the key interfacial properties of hydrogels, like friction and adhesion are not controlled by the stiffness, but are altered by the structure and composition of hydrogels, like polymer volume fraction and crosslinking degree. EXPERIMENTS Colloidal probe atomic force microscopy has been use to investigate the relationship between tribological properties (friction and adhesion) and composition of hydrogels with similar stiffness, but different polymer volume fractions and crosslinking degrees. FINDINGS The interfacial normal and lateral (friction) forces of hydrogels are not directly correlated to the stiffness, but altered by the hydrogel structure and composition. For normal force measurements, the adhesion increases with polymer volume fraction but decreases with crosslinking degree. For lateral force measurements, friction increases with polymer volume fraction, but decreases with crosslinking degree. In the low normal force regime, friction is mainly adhesion-controlled and increases significantly with the adhesion and polymer volume fraction. In the high normal force regime, friction is predominantly load-controlled and shows slow increase with normal force.
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Affiliation(s)
- Hua Li
- School of Molecular Sciences, The University of Western Australia, 35 Stirling Highway, Perth, WA 6009, Australia; Centre for Microscopy, Characterisation and Analysis, The University of Western Australia, Perth, WA 6009, Australia.
| | - Yu Suk Choi
- School of Human Sciences, The University of Western Australia, 35 Stirling Highway, Perth, WA 6009, Australia
| | - Mark W Rutland
- School of Chemical Science and Engineering, KTH Royal Institute of Technology, SE100 44, Sweden; Surfaces, Processes and Formulation, RISE Research Institutes of Sweden, SE114 86 Stockholm, Sweden
| | - Rob Atkin
- School of Molecular Sciences, The University of Western Australia, 35 Stirling Highway, Perth, WA 6009, Australia
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16
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Liamas E, Connell SD, Ramakrishna SN, Sarkar A. Probing the frictional properties of soft materials at the nanoscale. NANOSCALE 2020; 12:2292-2308. [PMID: 31951242 DOI: 10.1039/c9nr07084b] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The understanding of friction in soft materials is of increasing importance due to the demands of industries such as healthcare, biomedical, food and personal care, the incorporation of soft materials into technology, and in the study of interacting biological interfaces. Many of these processes occur at the nanoscale, but even at micrometer length scales there are fundamental aspects of tribology that remain poorly understood. With the advent of Friction Force Microscopy (FFM), there have been many fundamental insights into tribological phenomena at the atomic scale, such as 'stick-slip' and 'super-lubricity'. This review examines the growing field of soft tribology, the experimental aspects of FFM and its underlying theory. Moving to the nanoscale changes the contact mechanics which govern adhesive forces, which in turn play a pivotal role in friction, along with the deformation of the soft interface and dissipative phenomena. We examine recent progress and future prospects in soft nanotribology.
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Affiliation(s)
- Evangelos Liamas
- Food Colloids and Bioprocessing Group, School of Food Science and Nutrition, University of Leeds, UK.
| | - Simon D Connell
- Molecular and Nanoscale Physics Group, School of Physics and Astronomy, University of Leeds, UK
| | | | - Anwesha Sarkar
- Food Colloids and Bioprocessing Group, School of Food Science and Nutrition, University of Leeds, UK.
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17
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Affiliation(s)
- Piotr Mocny
- Institut des Matériaux and Institut des Sciences et Ingénierie Chimiques, Laboratoire des Polymères, École Polytechnique Fédérale de Lausanne (EPFL), Bâtiment MXD, Station 12, CH-1015 Lausanne, Switzerland
| | - Harm-Anton Klok
- Institut des Matériaux and Institut des Sciences et Ingénierie Chimiques, Laboratoire des Polymères, École Polytechnique Fédérale de Lausanne (EPFL), Bâtiment MXD, Station 12, CH-1015 Lausanne, Switzerland
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18
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Mocny P, Klok HA. Complex polymer topologies and polymer—nanoparticle hybrid films prepared via surface-initiated controlled radical polymerization. Prog Polym Sci 2020. [DOI: 10.1016/j.progpolymsci.2019.101185] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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19
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Itagaki N, Kawaguchi D, Oda Y, Nemoto F, Yamada NL, Yamaguchi T, Tanaka K. Surface Effect on Frictional Properties for Thin Hydrogel Films of Poly(vinyl ether). Macromolecules 2019. [DOI: 10.1021/acs.macromol.9b01786] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
| | | | | | - Fumiya Nemoto
- Neutron Science Laboratory, High Energy Accelerator Research Organization, Naka, Ibaraki 319-1106, Japan
| | - Norifumi L. Yamada
- Neutron Science Laboratory, High Energy Accelerator Research Organization, Naka, Ibaraki 319-1106, Japan
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20
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Yan W, Ramakrishna SN, Romio M, Benetti EM. Bioinert and Lubricious Surfaces by Macromolecular Design. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:13521-13535. [PMID: 31532689 DOI: 10.1021/acs.langmuir.9b02316] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The modification of a variety of biomaterials and medical devices often encompasses the generation of biopassive and lubricious layers on their exposed surfaces. This is valid when the synthetic supports are required to integrate within physiological media without altering their interfacial composition and when the minimization of shear stress prevents or reduces damage to the surrounding environment. In many of these cases, hydrophilic polymer brushes assembled from surface-interacting polymer adsorbates or directly grown by surface-initiated polymerizations (SIP) are chosen. Although growing efforts by polymer chemists have been focusing on varying the composition of polymer brushes in order to attain increasingly bioinert and lubricious surfaces, the precise modulation of polymer architecture has simultaneously enabled us to substantially broaden the tuning potential for the above-mentioned properties. This feature article concentrates on reviewing this latter strategy, comparatively analyzing how polymer brush parameters such as molecular weight and grafting density, the application of block copolymers, the introduction of branching and cross-links, or the variation of polymer topology beyond the simple, linear chains determine highly technologically relevant properties, such as biopassivity and lubrication.
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Affiliation(s)
- Wenqing Yan
- Polymer Surfaces Group, Laboratory for Surface Science and Technology, Department of Materials , Swiss Federal Institute of Technology (ETH Zürich) , Vladimir-Prelog-Weg 1-5/10 , CH-8093 Zurich , Switzerland
| | - Shivaprakash N Ramakrishna
- Polymer Surfaces Group, Laboratory for Surface Science and Technology, Department of Materials , Swiss Federal Institute of Technology (ETH Zürich) , Vladimir-Prelog-Weg 1-5/10 , CH-8093 Zurich , Switzerland
| | - Matteo Romio
- Polymer Surfaces Group, Laboratory for Surface Science and Technology, Department of Materials , Swiss Federal Institute of Technology (ETH Zürich) , Vladimir-Prelog-Weg 1-5/10 , CH-8093 Zurich , Switzerland
- Biointerfaces, Swiss Federal Laboratories for Materials Science and Technology (Empa) , Lerchenfeldstrasse 5 , CH-9014 St. Gallen , Switzerland
| | - Edmondo M Benetti
- Polymer Surfaces Group, Laboratory for Surface Science and Technology, Department of Materials , Swiss Federal Institute of Technology (ETH Zürich) , Vladimir-Prelog-Weg 1-5/10 , CH-8093 Zurich , Switzerland
- Biointerfaces, Swiss Federal Laboratories for Materials Science and Technology (Empa) , Lerchenfeldstrasse 5 , CH-9014 St. Gallen , Switzerland
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21
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Moreno-Guerra JA, Romero-Sánchez IC, Martinez-Borquez A, Tassieri M, Stiakakis E, Laurati M. Model-Free Rheo-AFM Probes the Viscoelasticity of Tunable DNA Soft Colloids. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2019; 15:e1904136. [PMID: 31460707 DOI: 10.1002/smll.201904136] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Indexed: 05/23/2023]
Abstract
Atomic force microscopy rheological measurements (Rheo-AFM) of the linear viscoelastic properties of single, charged colloids having a star-like architecture with a hard core and an extended, deformable double-stranded DNA (dsDNA) corona dispersed in aqueous saline solutions are reported. This is achieved by analyzing indentation and relaxation experiments performed on individual colloidal particles by means of a novel model-free Fourier transform method that allows a direct evaluation of the frequency-dependent linear viscoelastic moduli of the system under investigation. The method provides results that are consistent with those obtained via a conventional fitting procedure of the force-relaxation curves based on a modified Maxwell model. The outcomes show a pronounced softening of the dsDNA colloids, which is described by an exponential decay of both the Young's and the storage modulus as a function of the salt concentration within the dispersing medium. The strong softening is related to a critical reduction of the size of the dsDNA corona, down to ≈70% of its size in a salt-free solution. This can be correlated to significant topological changes of the dense star-like polyelectrolyte forming the corona, which are induced by variations in the density profile of the counterions. Similarly, a significant reduction of the stiffness is obtained by increasing the length of the dsDNA chains, which we attribute to a reduction of the DNA density in the outer region of the corona.
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Affiliation(s)
- José A Moreno-Guerra
- División de Ciencias e Ingenierías, Universidad de Guanajuato, Lomas del Bosque 103, 37150, León, Mexico
| | - Ivany C Romero-Sánchez
- División de Ciencias e Ingenierías, Universidad de Guanajuato, Lomas del Bosque 103, 37150, León, Mexico
| | - Alejandro Martinez-Borquez
- División de Ciencias e Ingenierías, Universidad de Guanajuato, Lomas del Bosque 103, 37150, León, Mexico
| | - Manlio Tassieri
- Division of Biomedical Engineering, School of Engineering, University of Glasgow, Glasgow, G12 8LT, UK
| | - Emmanuel Stiakakis
- Forschungszentrum Jülich, Institute of Complex Systems 3, Leo-Brandt-Strasse, 52425, Jülich, Germany
| | - Marco Laurati
- División de Ciencias e Ingenierías, Universidad de Guanajuato, Lomas del Bosque 103, 37150, León, Mexico
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22
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Yuan Z, Wang J, Niu X, Ma J, Qin X, Li L, Shi L, Wu Y, Guo X. A Study of the Surface Adhesion and Rheology Properties of Cationic Conditioning Polymers. Ind Eng Chem Res 2019. [DOI: 10.1021/acs.iecr.9b00054] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Zhenyu Yuan
- State Key Laboratory of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, People’s Republic of China
| | - Jie Wang
- State Key Laboratory of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, People’s Republic of China
| | - Xiaofeng Niu
- State Key Laboratory of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, People’s Republic of China
| | - Jun Ma
- State Key Laboratory of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, People’s Republic of China
| | - Xue Qin
- State Key Laboratory of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, People’s Republic of China
| | - Li Li
- State Key Laboratory of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, People’s Republic of China
| | - Lei Shi
- Firmenich Aromatics (China) Co., Ltd., Shanghai 201108, People’s Republic of China
| | - Yongtao Wu
- Firmenich Aromatics (China) Co., Ltd., Shanghai 201108, People’s Republic of China
| | - Xuhong Guo
- State Key Laboratory of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, People’s Republic of China
- Engineering Research Center of Materials Chemical Engineering of Xinjiang Bingtuan, Shihezi University, Xinjiang 832000, People’s Republic of China
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23
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Benetti EM, Spencer ND. Using Polymers to Impart Lubricity and Biopassivity to Surfaces: Are These Properties Linked? Helv Chim Acta 2019. [DOI: 10.1002/hlca.201900071] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Edmondo M. Benetti
- Laboratory for Surface Science and Technology, Department of MaterialsETH Zurich Vladimir-Prelog-Weg 5 CH-8093 Zurich Switzerland
| | - Nicholas D. Spencer
- Laboratory for Surface Science and Technology, Department of MaterialsETH Zurich Vladimir-Prelog-Weg 5 CH-8093 Zurich Switzerland
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24
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Marschelke C, Puretskiy N, Raguzin I, Melnyk I, Ionov L, Synytska A. Effect of Architecture of Thermoresponsive Copolymer Brushes on Switching of Their Adsorption Properties. MACROMOL CHEM PHYS 2019. [DOI: 10.1002/macp.201900030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Claudia Marschelke
- Leibniz Institute of Polymer Research Dresden e.V. Hohe Str. 6 01069 Dresden Germany
- Institute of Physical Chemistry of Polymeric Materials Dresden University of Technology 01062 Dresden Germany
| | - Nikolay Puretskiy
- Leibniz Institute of Polymer Research Dresden e.V. Hohe Str. 6 01069 Dresden Germany
| | - Ivan Raguzin
- Leibniz Institute of Polymer Research Dresden e.V. Hohe Str. 6 01069 Dresden Germany
| | - Inga Melnyk
- Leibniz Institute of Polymer Research Dresden e.V. Hohe Str. 6 01069 Dresden Germany
| | - Leonid Ionov
- Faculty of Engineering ScienceUniversity of Bayreuth, Universitätsstr. 30 95440 Bayreuth Germany
- Bavarian Polymer Institute, Universitätsstr. 30 95440 Bayreuth Germany
| | - Alla Synytska
- Leibniz Institute of Polymer Research Dresden e.V. Hohe Str. 6 01069 Dresden Germany
- Institute of Physical Chemistry of Polymeric Materials Dresden University of Technology 01062 Dresden Germany
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25
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Benetti EM. Quasi-3D-Structured Interfaces by Polymer Brushes. Macromol Rapid Commun 2018; 39:e1800189. [DOI: 10.1002/marc.201800189] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 04/10/2018] [Indexed: 11/10/2022]
Affiliation(s)
- Edmondo M. Benetti
- Polymer Surfaces Group; Laboratory for Surface Science and Technology; Department of Materials; ETH Zürich; Vladimir-Prelog-Weg 5/10 8093 Zürich Switzerland
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26
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Lei R, Lee JP, Francis MB, Kumar S. Structural Regulation of a Neurofilament-Inspired Intrinsically Disordered Protein Brush by Multisite Phosphorylation. Biochemistry 2018; 57:4019-4028. [PMID: 29557644 DOI: 10.1021/acs.biochem.8b00007] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Intrinsically disordered proteins (IDPs) play central roles in numerous cellular processes. While IDP structure and function are often regulated by multisite phosphorylation, the biophysical mechanisms linking these post-translational modifications to IDP structure remain elusive. For example, the intrinsically disordered C-terminal sidearm domain of the neurofilament heavy subunit (NFH-SA) forms a dense brush along axonal NF backbones and is subject to extensive serine phosphorylation. Yet, biophysical insight into the relationship between phosphorylation and structure has been limited by the lack of paradigms in which NF brush conformational responses can be measured in the setting of controlled phosphorylation. Here, we approach this question by immobilizing a recombinant NFH-SA (rNFH-SA) as IDP brushes onto glass, and controllably phosphorylating the sequence in situ with mitogen-activated protein kinase 1 (ERK2) preactivated by mitogen-activated protein kinase kinase (MKK). We then monitor brush height changes using atomic force microscopy, which shows that phosphorylation induces significant brush swelling to an extent that strongly depends upon pH and ionic strength, consistent with a mechanism in which phosphorylation regulates brush structure through local electrostatic interactions. Further consistent with this mechanism, the phosphorylated rNFH-SA brush may be dramatically condensed with micromolar concentrations of divalent cations. Phosphorylation-induced height changes are qualitatively reversible via alkaline phosphatase-mediated dephosphorylation. Our study demonstrates that multisite phosphorylation controls NFH-SA structure through modulation of chain electrostatics and points to a general strategy for engineering IDP-based interfaces that can be reversibly and dynamically modulated by enzymes.
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Affiliation(s)
| | | | - Matthew B Francis
- Materials Sciences Division , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
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27
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Soliman AIA, Utsunomiya T, Ichii T, Sugimura H. Vacuum Ultraviolet Treatment of Acid- and Ester-Terminated Self-Assembled Monolayers: Chemical Conversions and Friction Reduction. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:3228-3236. [PMID: 29451390 DOI: 10.1021/acs.langmuir.7b04327] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We have prepared COOH- and COOCH3-terminated self-assembled monolayers (SAMs) from undec-10-enoic acid (UDA) and methyl undec-10-enoate (MUDO) molecules on hydrogen-terminated silicon (H-Si) substrates through ultraviolet (UV) irradiation. The as-prepared UDA- and MUDO-SAMs were exposed to 172 nm vacuum-UV (VUV) light in a high vacuum environment (HV, <10-3 Pa) for different periods. The presence of COO components at the surfaces of these SAMs without prior oxidation would simplify the understanding of the origin of the chemical conversions and the changes of surface properties, as the prior oxidation would change the surface properties and generate different oxygenated groups. After the HV-VUV treatment, the abundance of COOH and COOCH3 components of these SAMs decreased without significant dissociation of their C-C backbones. Degradation of these components occurred through dissociating their C-O bonds, resulting in different C═O components. Also, the occurrence of Norrish type pathways resulted in a slight decrease of carbon content and produced CH3 components. We have applied the HV-VUV lithography to control the abundance of COOH and COOCH3 components in well-defined areas and to investigate the friction differences between the irradiated and masked areas. The irradiated areas exhibited lower friction than the masked areas without observing significant height contrasts between these areas. The reduction in friction was attributed to the conversion of the COOH and COOCH3 components to less adhesive components such as C═O and CH3. These experiments suggest the HV-VUV treatments as an approach for low damage dry surface modifications and reductive lithographic techniques at surfaces terminated by acid and ester groups.
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Affiliation(s)
- Ahmed I A Soliman
- Department of Materials Science and Engineering , Kyoto University , Yoshida-Hommachi , Sakyo-ku, Kyoto 606-8501 , Japan
| | - Toru Utsunomiya
- Department of Materials Science and Engineering , Kyoto University , Yoshida-Hommachi , Sakyo-ku, Kyoto 606-8501 , Japan
| | - Takashi Ichii
- Department of Materials Science and Engineering , Kyoto University , Yoshida-Hommachi , Sakyo-ku, Kyoto 606-8501 , Japan
| | - Hiroyuki Sugimura
- Department of Materials Science and Engineering , Kyoto University , Yoshida-Hommachi , Sakyo-ku, Kyoto 606-8501 , Japan
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28
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Nautiyal P, Alam F, Balani K, Agarwal A. The Role of Nanomechanics in Healthcare. Adv Healthc Mater 2018; 7. [PMID: 29193838 DOI: 10.1002/adhm.201700793] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Revised: 09/18/2017] [Indexed: 12/21/2022]
Abstract
Nanomechanics has played a vital role in pushing our capability to detect, probe, and manipulate the biological species, such as proteins, cells, and tissues, paving way to a deeper knowledge and superior strategies for healthcare. Nanomechanical characterization techniques, such as atomic force microscopy, nanoindentation, nanotribology, optical tweezers, and other hybrid techniques have been utilized to understand the mechanics and kinetics of biospecies. Investigation of the mechanics of cells and tissues has provided critical information about mechanical characteristics of host body environments. This information has been utilized for developing biomimetic materials and structures for tissue engineering and artificial implants. This review summarizes nanomechanical characterization techniques and their potential applications in healthcare research. The principles and examples of label-free detection of cancers and myocardial infarction by nanomechanical cantilevers are discussed. The vital importance of nanomechanics in regenerative medicine is highlighted from the perspective of material selection and design for developing biocompatible scaffolds. This review interconnects the advancements made in fundamental materials science research and biomedical technology, and therefore provides scientific insight that is of common interest to the researchers working in different disciplines of healthcare science and technology.
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Affiliation(s)
- Pranjal Nautiyal
- Nanomechanics and Nanotribology Laboratory Florida International University 10555 West Flagler Street Miami FL 33174 USA
| | - Fahad Alam
- Biomaterials Processing and Characterization Laboratory Department of Materials Science and Engineering Indian Institute of Technology Kanpur Kanpur 208016 India
| | - Kantesh Balani
- Biomaterials Processing and Characterization Laboratory Department of Materials Science and Engineering Indian Institute of Technology Kanpur Kanpur 208016 India
| | - Arvind Agarwal
- Nanomechanics and Nanotribology Laboratory Florida International University 10555 West Flagler Street Miami FL 33174 USA
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29
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Investigating the structure of crosslinked polymer brushes (brush-gels) by means of Positron Annihilation Spectroscopy. Eur Polym J 2018. [DOI: 10.1016/j.eurpolymj.2017.12.042] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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30
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Yu K, Hodges C, Biggs S, Cayre OJ, Harbottle D. Polymer Molecular Weight Dependence on Lubricating Particle–Particle Interactions. Ind Eng Chem Res 2018. [DOI: 10.1021/acs.iecr.7b04609] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- Kai Yu
- School
of Chemical and Process Engineering, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Chris Hodges
- School
of Chemical and Process Engineering, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Simon Biggs
- Faculty
of Engineering, Architecture and Information Technology, The University of Queensland, St Lucia, Queensland 4072, Australia
| | - Olivier J. Cayre
- School
of Chemical and Process Engineering, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - David Harbottle
- School
of Chemical and Process Engineering, University of Leeds, Leeds LS2 9JT, United Kingdom
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31
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Raftari M, Zhang ZJ, Carter SR, Leggett GJ, Geoghegan M. Salt Dependence of the Tribological Properties of a Surface-Grafted Weak Polycation in Aqueous Solution. TRIBOLOGY LETTERS 2017; 66:11. [PMID: 31983863 PMCID: PMC6951817 DOI: 10.1007/s11249-017-0963-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Accepted: 11/23/2017] [Indexed: 06/10/2023]
Abstract
The nanoscopic adhesive and frictional behaviour of end-grafted poly[2-(dimethyl amino)ethyl methacrylate] (PDMAEMA) films (brushes) in contact with gold- or PDMAEMA-coated atomic force microscope tips in potassium halide solutions with different concentrations up to 300 mM is a strong function of salt concentration. The conformation of the polymers in the brush layer is sensitive to salt concentration, which leads to large changes in adhesive forces and the contact mechanics at the tip-sample contact, with swollen brushes (which occur at low salt concentrations) yielding large areas of contact and friction-load plots that fit JKR behaviour, while collapsed brushes (which occur at high salt concentrations) yield sliding dominated by ploughing, with conformations in between fitting DMT mechanics. The relative effect of the different anions follows the Hofmeister series, with I- collapsing the brushes more than Br- and Cl- for the same salt concentration.
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Affiliation(s)
- Maryam Raftari
- Department of Physics and Astronomy, University of Sheffield, Sheffield, S3 7RH UK
| | - Zhenyu J. Zhang
- Department of Chemistry, University of Sheffield, Sheffield, S3 7HF UK
- Present Address: School of Chemical Engineering, University of Birmingham, Birmingham, B15 2TT UK
| | - Steven R. Carter
- Department of Physics and Astronomy, University of Sheffield, Sheffield, S3 7RH UK
| | - Graham J. Leggett
- Department of Chemistry, University of Sheffield, Sheffield, S3 7HF UK
| | - Mark Geoghegan
- Department of Physics and Astronomy, University of Sheffield, Sheffield, S3 7RH UK
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32
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Wang D, Russell TP. Advances in Atomic Force Microscopy for Probing Polymer Structure and Properties. Macromolecules 2017. [DOI: 10.1021/acs.macromol.7b01459] [Citation(s) in RCA: 89] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
| | - Thomas P. Russell
- Polymer
Science and Engineering Department, University of Massachusetts Amherst, Amherst, Massachusetts 01003, United States
- Materials
Sciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, United States
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