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Kim YC, Composto RJ, Winey KI. pH-Mediated Size-Selective Adsorption of Gold Nanoparticles on Diblock Copolymer Brushes. ACS NANO 2023; 17:9224-9234. [PMID: 37134256 DOI: 10.1021/acsnano.3c00212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Precise control of nanoparticles at interfaces can be achieved by designing stimuli-responsive surfaces that have tunable interactions with nanoparticles. In this study, we demonstrate that a polymer brush can selectively adsorb nanoparticles according to size by tuning the pH of the buffer solution. Specifically, we developed a facile polymer brush preparation method using a symmetric polystyrene-b-poly(2-vinylpyridine) (PS-b-P2VP) block copolymer deposited on a grafted polystyrene layer. This method is based on the assembly of a PS-b-P2VP thin film oriented with parallel lamellae that remains after exfoliation of the top PS-b-P2VP layer. We characterized the P2VP brush using X-ray reflectivity and atomic force microscopy. The buffer pH is used to tailor interactions between citrate-coated gold nanoparticles (AuNPs) and the top P2VP block that behaves like a polymer brush. At low pH (∼4.0) the P2VP brushes are strongly stretched and display a high density of attractive sites, whereas at neutral pH (∼6.5) the P2VP brushes are only slightly stretched and have fewer attractive sites. A quartz crystal microbalance with dissipation monitored the adsorption thermodynamics as a function of AuNP diameter (11 and 21 nm) and pH of the buffer. Neutral pH provides limited penetration depth for nanoparticles and promotes size selectivity for 11 nm AuNP adsorption. As a proof of concept, the P2VP brushes were exposed to various mixtures of large and small AuNPs to demonstrate selective capture of the smaller AuNPs. This study shows the potential of creating devices for nanoparticle size separations using pH-sensitive polymer brushes.
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Affiliation(s)
- Ye Chan Kim
- Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Russell J Composto
- Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Karen I Winey
- Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
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Winkler R, Beena Unni A, Tu W, Chat K, Adrjanowicz K. On the Segmental Dynamics and the Glass Transition Behavior of Poly(2-vinylpyridine) in One- and Two-Dimensional Nanometric Confinement. J Phys Chem B 2021; 125:5991-6003. [PMID: 34048244 PMCID: PMC8279553 DOI: 10.1021/acs.jpcb.1c01245] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 05/13/2021] [Indexed: 11/30/2022]
Abstract
Geometric nanoconfinement, in one and two dimensions, has a fundamental influence on the segmental dynamics of polymer glass-formers and can be markedly different from that observed in the bulk state. In this work, with the use of dielectric spectroscopy, we have investigated the glass transition behavior of poly(2-vinylpyridine) (P2VP) confined within alumina nanopores and prepared as a thin film supported on a silicon substrate. P2VP is known to exhibit strong, attractive interactions with confining surfaces due to the ability to form hydrogen bonds. Obtained results show no changes in the temperature evolution of the α-relaxation time in nanopores down to 20 nm size and 24 nm thin film. There is also no evidence of an out-of-equilibrium behavior observed for other glass-forming systems confined at the nanoscale. Nevertheless, in both cases, the confinement effect is seen as a substantial broadening of the α-relaxation time distribution. We discussed the results in terms of the importance of the interfacial energy between the polymer and various substrates, the sensitivity of the glass-transition temperature to density fluctuations, and the density scaling concept.
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Affiliation(s)
- Roksana Winkler
- Institute
of Physics, University of Silesia, 75 Pulku Piechoty 1, 41-500 Chorzow, Poland
- Silesian
Center for Education and Interdisciplinary Research (SMCEBI), 75 Pulku Piechoty 1a, 41-500 Chorzow, Poland
| | - Aparna Beena Unni
- Institute
of Physics, University of Silesia, 75 Pulku Piechoty 1, 41-500 Chorzow, Poland
- Silesian
Center for Education and Interdisciplinary Research (SMCEBI), 75 Pulku Piechoty 1a, 41-500 Chorzow, Poland
| | - Wenkang Tu
- Institute
of Physics, University of Silesia, 75 Pulku Piechoty 1, 41-500 Chorzow, Poland
- Silesian
Center for Education and Interdisciplinary Research (SMCEBI), 75 Pulku Piechoty 1a, 41-500 Chorzow, Poland
| | - Katarzyna Chat
- Institute
of Physics, University of Silesia, 75 Pulku Piechoty 1, 41-500 Chorzow, Poland
- Silesian
Center for Education and Interdisciplinary Research (SMCEBI), 75 Pulku Piechoty 1a, 41-500 Chorzow, Poland
| | - Karolina Adrjanowicz
- Institute
of Physics, University of Silesia, 75 Pulku Piechoty 1, 41-500 Chorzow, Poland
- Silesian
Center for Education and Interdisciplinary Research (SMCEBI), 75 Pulku Piechoty 1a, 41-500 Chorzow, Poland
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Huang X, Roth CB. Optimizing the Grafting Density of Tethered Chains to Alter the Local Glass Transition Temperature of Polystyrene near Silica Substrates: The Advantage of Mushrooms over Brushes. ACS Macro Lett 2018; 7:269-274. [PMID: 35610905 DOI: 10.1021/acsmacrolett.8b00019] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We measured the local glass transition temperature Tg(z) of polystyrene (PS) as a function of distance z from a silica substrate with end-grafted chains using fluorescence, where competing effects from the free surface have been avoided to focus only on the influence of the tethered interface. The local Tg(z) increase next to the chain-grafted substrate is found to exhibit a maximum increase of 49 ± 2 K relative to bulk at an optimum grafting density that corresponds to the mushroom-to-brush transition regime. This perturbation to the local Tg(z) dynamics of the matrix is observed to persist out to a distance z ≈ 100-125 nm for this optimum grafting density before bulk Tg is recovered, a distance comparable to that previously observed by Baglay and Roth [J. Chem. Phys. 2017, 146, 203307] for PS next to the higher-Tg polymer polysulfone.
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Affiliation(s)
- Xinru Huang
- Department of Physics, Emory University, Atlanta, Georgia 30322, United States
| | - Connie B. Roth
- Department of Physics, Emory University, Atlanta, Georgia 30322, United States
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Zuo B, Zhang S, Niu C, Zhou H, Sun S, Wang X. Grafting density dominant glass transition of dry polystyrene brushes. SOFT MATTER 2017; 13:2426-2436. [PMID: 28150841 DOI: 10.1039/c6sm02790c] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The effects of the grafting densities (σp), molecular weights (Mn) and thicknesses of dry polystyrene (PS) brushes on their glass transition temperature (T) were investigated by ellipsometry. The results show that T strongly depends on the grafting density of the PS brushes. The T of the PS brushes with σp > 0.30 increases with decreasing Mn (or brush thickness) and is mainly dominated by entropic effects, in which the grafted chains are highly extended along the film thickness direction resulting in a sharp reduction in configurational entropy. The T of PS brushes with σp < 0.30 decreases with decreasing Mn (or brush thickness) which is mainly dominated by surface effects. For intermediate-density brushes (σp = 0.30), T becomes independent of Mn or brush thickness. The reason for this grafting density dependence of T is attributed to the transition of the PS brush conformation from mushroom-to-brush.
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Affiliation(s)
- Biao Zuo
- Department of Chemistry, Key Laboratory of Advanced Textile Materials and Manufacturing Technology of Education Ministry, Zhejiang Sci-Tech University, Hangzhou 310018, China.
| | - Shasha Zhang
- Department of Chemistry, Key Laboratory of Advanced Textile Materials and Manufacturing Technology of Education Ministry, Zhejiang Sci-Tech University, Hangzhou 310018, China.
| | - Chen Niu
- Department of Chemistry, Key Laboratory of Advanced Textile Materials and Manufacturing Technology of Education Ministry, Zhejiang Sci-Tech University, Hangzhou 310018, China.
| | - Hao Zhou
- Department of Chemistry, Key Laboratory of Advanced Textile Materials and Manufacturing Technology of Education Ministry, Zhejiang Sci-Tech University, Hangzhou 310018, China.
| | - Shuzheng Sun
- Department of Chemistry, Key Laboratory of Advanced Textile Materials and Manufacturing Technology of Education Ministry, Zhejiang Sci-Tech University, Hangzhou 310018, China.
| | - Xinping Wang
- Department of Chemistry, Key Laboratory of Advanced Textile Materials and Manufacturing Technology of Education Ministry, Zhejiang Sci-Tech University, Hangzhou 310018, China.
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Madkour S, Szymoniak P, Heidari M, von Klitzing R, Schönhals A. Unveiling the Dynamics of Self-Assembled Layers of Thin Films of Poly(vinyl methyl ether) (PVME) by Nanosized Relaxation Spectroscopy. ACS APPLIED MATERIALS & INTERFACES 2017; 9:7535-7546. [PMID: 28155271 DOI: 10.1021/acsami.6b14404] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
A combination of nanosized dielectric relaxation (BDS) and thermal spectroscopy (SHS) was utilized to characterize the dynamics of thin films of poly(vinyl methyl ether) (PVME) (thicknesses: 7-160 nm). For the BDS measurements, a recently designed nanostructured electrode system is employed. A thin film is spin-coated on an ultraflat highly conductive silicon wafer serving as the bottom electrode. As top electrode, a highly conductive wafer with nonconducting nanostructured SiO2 nanospacers with heights of 35 or 70 nm is assembled on the bottom electrode. This procedure results in thin supported films with a free polymer/air interface. The BDS measurements show two relaxation processes, which are analyzed unambiguously for thicknesses smaller than 50 nm. The relaxation rates of both processes have different temperature dependencies. One process coincides in its position and temperature dependence with the glassy dynamics of bulk PVME and is ascribed to the dynamic glass transition of a bulk-like layer in the middle of the film. The relaxation rates were found to be thickness independent as confirmed by SHS. Unexpectedly, the relaxation rates of the second process obey an Arrhenius-like temperature dependence. This process was not observed by SHS and was related to the constrained fluctuations in a layer, which is irreversibly adsorbed at the substrate with a heterogeneous structure. Its molecular fluctuations undergo a confinement effect resulting in the localization of the segmental dynamics. To our knowledge, this is the first report on the molecular dynamics of an adsorbed layer in thin films.
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Affiliation(s)
- Sherif Madkour
- Bundesanstalt für Materialforschung und Prüfung (BAM) , Unter den Eichen 87, 12205 Berlin, Germany
| | - Paulina Szymoniak
- Bundesanstalt für Materialforschung und Prüfung (BAM) , Unter den Eichen 87, 12205 Berlin, Germany
| | - Mojdeh Heidari
- Stranski-Laboratorium für Physikalische und Theoretische Chemie, Institut für Chemie, Technische Universität Berlin , Straße des 17, Juni 124, 10623 Berlin, Germany
| | - Regine von Klitzing
- Stranski-Laboratorium für Physikalische und Theoretische Chemie, Institut für Chemie, Technische Universität Berlin , Straße des 17, Juni 124, 10623 Berlin, Germany
| | - Andreas Schönhals
- Bundesanstalt für Materialforschung und Prüfung (BAM) , Unter den Eichen 87, 12205 Berlin, Germany
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6
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Mayoral E, Klapp J, Gama Goicochea A. Scaling features of the tribology of polymer brushes of increasing grafting density around the mushroom-to-brush transition. Phys Rev E 2017; 95:012505. [PMID: 28208340 DOI: 10.1103/physreve.95.012505] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Indexed: 11/07/2022]
Abstract
Nonequilibrium coarse-grained, dissipative particle dynamics simulations of complex fluids, made up of polymer brushes tethered to planar surfaces immersed in a solvent yield nonmonotonic behavior of the friction coefficient as a function of the polymer grating density on the substrates, Γ, while the viscosity shows a monotonically increasing dependence on Γ. This effect is shown to be independent of the degree of polymerization, N, and the size of the system. It arises from the composition and the structure of the first particle layer adjacent to each surface that results from the confinement of the fluid. Whenever such layers are made up of as close a proportion of polymer beads to solvent particles as there are in the fluid, the friction coefficient shows a minimum, while for disparate proportions the friction coefficient grows. At the mushroom-to-brush transition (MBT) the viscosity scales with an exponent that depends on the characteristic exponent of the MBT (6/5) and the solvent quality exponent (ν=0.5, for θsolvent), but it is independent of the polymerization degree (N). On the other hand, the friction coefficient at the MBT scales as μ∼N^{6/5}, while the grafting density at the MBT scales as Γ∼N^{-6/5} when friction is minimal, in agreement with previous scaling theories. We argue these aspects are the result of cooperative phenomena that have important implications for the understanding of biological brushes and the design of microfluidics devices, among other applications of current academic and industrial interest.
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Affiliation(s)
- E Mayoral
- Instituto Nacional de Investigaciones Nucleares, Carretera México-Toluca s/n, La Marquesa Ocoyoacac, Estado de México 52750, Mexico
| | - J Klapp
- Instituto Nacional de Investigaciones Nucleares, Carretera México-Toluca s/n, La Marquesa Ocoyoacac, Estado de México 52750, Mexico.,"ABACUS" Centro de Matemáticas Aplicadas y Cómputo de Alto Rendimiento, Departamento de Matemáticas, Centro de Investigación y de Estudios Avanzados (CINVESTAV-IPN), Carretera México-Toluca Km 38.5, La Marquesa, Ocoyoacac, Estado de México 52740, Mexico
| | - A Gama Goicochea
- División de Ingeniería Química y Bioquímica, Tecnológico de Estudios Superiores de Ecatepec, Avenida Tecnológico s/n, Ecatepec, Estado de México 55210, Mexico
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Alegria A, Colmenero J. Dielectric relaxation of polymers: segmental dynamics under structural constraints. SOFT MATTER 2016; 12:7709-25. [PMID: 27560167 DOI: 10.1039/c6sm01298a] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
In this article we review the recent polymer literature where dielectric spectroscopy has been used to investigate the segmental dynamics of polymers under the constraints produced by self-structuring. Specifically, we consider three cases: (i) semicrystalline polymers, (ii) segregated block-copolymers, and (iii) asymmetric miscible polymer blends. In these three situations the characteristics of the dielectric relaxation associated with the polymer segmental dynamics are markedly affected by the constraints imposed by the corresponding structural features. After reviewing in detail each of the polymer systems, the most common aspects are discussed in the context of the use of dielectric relaxation as a sensitive tool for analyzing structural features in nanostructured polymer systems.
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Affiliation(s)
- Angel Alegria
- Centro de Física de Materiales (CSIC-UPV/EHU), Paseo Manuel Lardizabal 5, 20018 San Sebastián, Spain.
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Neubauer N, Treß M, Winkler R, Mapesa EU, Kipnusu WK, Uhlmann P, Kremer F. Molecular Dynamics of Swollen Poly(2-vinylpyridine) Brushes. Macromolecules 2016. [DOI: 10.1021/acs.macromol.6b00363] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Nils Neubauer
- Institute
of Experimental Physics I, Leipzig University, 04103 Leipzig, Germany
| | - Martin Treß
- Department
of Chemistry, University of Tennessee, Knoxville, Tennessee 37996-1600, United States
| | - René Winkler
- Leibniz-Institut
für Polymerforschung Dresden e.V., 01069 Dresden, Germany
| | | | - Wycliffe Kiprop Kipnusu
- Institute
of Experimental Physics I, Leipzig University, 04103 Leipzig, Germany
- Leibniz-Institut
für Oberflächenmodifizierung e.V., 04318 Leipzig, Germany
| | - Petra Uhlmann
- Leibniz-Institut
für Polymerforschung Dresden e.V., 01069 Dresden, Germany
| | - Friedrich Kremer
- Institute
of Experimental Physics I, Leipzig University, 04103 Leipzig, Germany
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9
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From Self-Assembled Monolayers to Coatings: Advances in the Synthesis and Nanobio Applications of Polymer Brushes. Polymers (Basel) 2015. [DOI: 10.3390/polym7071346] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
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