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Li M, Pester CW. Mixed Polymer Brushes for "Smart" Surfaces. Polymers (Basel) 2020; 12:E1553. [PMID: 32668820 PMCID: PMC7408536 DOI: 10.3390/polym12071553] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 07/09/2020] [Accepted: 07/10/2020] [Indexed: 12/26/2022] Open
Abstract
Mixed polymer brushes (MPBs) are composed of two or more disparate polymers covalently tethered to a substrate. The resulting phase segregated morphologies have been extensively studied as responsive "smart" materials, as they can be reversible tuned and switched by external stimuli. Both computational and experimental work has attempted to establish an understanding of the resulting nanostructures that vary as a function of many factors. This contribution highlights state-of-the-art MPBs studies, covering synthetic approaches, phase behavior, responsiveness to external stimuli as well as novel applications of MPBs. Current limitations are recognized and possible directions for future studies are identified.
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Affiliation(s)
- Mingxiao Li
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA 16802, USA;
| | - Christian W. Pester
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA 16802, USA;
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA 16802, USA
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, USA
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Mu D, Li JQ, Cong XS, Mi YW, Zhang H. Solvent Effect on the Self-Assembly of a Thin Film Consisting of Y-Shaped Copolymer. Polymers (Basel) 2019; 11:polym11020261. [PMID: 30960246 PMCID: PMC6419031 DOI: 10.3390/polym11020261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Revised: 01/30/2019] [Accepted: 01/31/2019] [Indexed: 11/16/2022] Open
Abstract
The self-assembly of an amphiphilic Y-shaped copolymer consisting of two hydrophilic branches and one hydrophobic branch in a thin film is investigated under different conditions by virtue of mesoscopic computer modelling, accompanied by doping with a single solvent, doping with a binary solvent, and those solvent environments together with the introduction of confinement defined by various acting distances and influencing regions. A cylindrical micellar structure is maintained, as it is in the thin film with the doping of either 10% hydrophobic solvent or 10% hydrophilic solvent, whose structure consists of the hydrophobic core and hydrophilic shell. Attributed to the hydrophobicity/hydrophilia nature of the solvents, different solvents play an obvious role on the self-assembled structure, i.e., the hydrophobic solvent presents as a swelling effect, conversely, the hydrophilic solvent presents as a shrinking effect. Further, the synergistic effect of the binary solvents on the self-assembly produces the lowest values in both the average volumetric size and free energy density when the quantity of hydrophobic solvent and hydrophilic solvent is equivalent. Interestingly, the solvent effect becomes more pronounced under the existent of a confinement. When a lateral-oriented confinement is introduced, a periodically fluctuating change in the cylindrical size occurs in two near-wall regions, but the further addition of either hydrophobic or hydrophilic solvent can effectively eliminate such resulting hierarchical-sized cylinders and generate uniform small-sized cylinders. However, with the introduction of a horizontal-orientated confinement, the copolymers self-assemble into the spherical micellar structure. Moreover, the further addition of hydrophobic solvent leads to a decrease in the average size of micelles via coalescence mechanism, in contrast, the further addition of hydrophilic solvent causes an increase in the average size of micelles via splitting mechanism. These findings enrich our knowledge of the potential for the solvent effect on the self-assembly of amphiphilic copolymer system, and then provide theoretical supports on improving and regulating the mesoscopic structure of nanomaterials.
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Affiliation(s)
- Dan Mu
- College of Chemistry Chemical Engineering and Materials Science, Zaozhuang University, Zaozhuang 277160, China.
- Advanced Photonics Center, Southeast University, 2# Sipailou, Nanjing 210096, China.
| | - Jian-Quan Li
- Opto-Electronic Engineering College, Zaozhuang University, Zaozhuang 277160, China.
| | - Xing-Shun Cong
- College of Chemistry Chemical Engineering and Materials Science, Zaozhuang University, Zaozhuang 277160, China.
| | - Yu-Wei Mi
- College of Chemistry Chemical Engineering and Materials Science, Zaozhuang University, Zaozhuang 277160, China.
| | - Han Zhang
- College of Chemistry Chemical Engineering and Materials Science, Zaozhuang University, Zaozhuang 277160, China.
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Lazutin AA, Vasilevskaya VV, Khokhlov AR. Self-assembly in densely grafted macromolecules with amphiphilic monomer units: diagram of states. SOFT MATTER 2017; 13:8525-8533. [PMID: 29091101 DOI: 10.1039/c7sm01560g] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
By means of computer modelling, the self-organization of dense planar brushes of macromolecules with amphiphilic monomer units was addressed and their state diagram was constructed. The diagram of states includes the following regions: disordered position of monomer units with respect to each other, strands composed of a few polymer chains and lamellae with different domain spacing. The transformation of lamellae structures with different domain spacing occurred within the intermediate region and could proceed through the formation of so-called parking garage structures. The parking garage structure joins the lamellae with large (on the top of the brushes) and small (close to the grafted surface) domain spacing, which appears like a system of inclined locally parallel layers connected with each other by bridges. The parking garage structures were observed for incompatible A and B groups in selective solvents, which result in aggregation of the side B groups and dense packing of amphiphilic macromolecules in the restricted volume of the planar brushes.
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Affiliation(s)
- A A Lazutin
- A. N. Nesmeyanov Institute of Organoelement Compounds RAS, Vavilova ul., 28, Moscow 119991, Russia.
| | - V V Vasilevskaya
- A. N. Nesmeyanov Institute of Organoelement Compounds RAS, Vavilova ul., 28, Moscow 119991, Russia.
| | - A R Khokhlov
- A. N. Nesmeyanov Institute of Organoelement Compounds RAS, Vavilova ul., 28, Moscow 119991, Russia. and Faculty of Physics, M. V. Lomonosov Moscow State University, Leninskie gory, Moscow 119991, Russia
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Zoppe JO, Ataman NC, Mocny P, Wang J, Moraes J, Klok HA. Surface-Initiated Controlled Radical Polymerization: State-of-the-Art, Opportunities, and Challenges in Surface and Interface Engineering with Polymer Brushes. Chem Rev 2017; 117:1105-1318. [PMID: 28135076 DOI: 10.1021/acs.chemrev.6b00314] [Citation(s) in RCA: 578] [Impact Index Per Article: 82.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The generation of polymer brushes by surface-initiated controlled radical polymerization (SI-CRP) techniques has become a powerful approach to tailor the chemical and physical properties of interfaces and has given rise to great advances in surface and interface engineering. Polymer brushes are defined as thin polymer films in which the individual polymer chains are tethered by one chain end to a solid interface. Significant advances have been made over the past years in the field of polymer brushes. This includes novel developments in SI-CRP, as well as the emergence of novel applications such as catalysis, electronics, nanomaterial synthesis and biosensing. Additionally, polymer brushes prepared via SI-CRP have been utilized to modify the surface of novel substrates such as natural fibers, polymer nanofibers, mesoporous materials, graphene, viruses and protein nanoparticles. The last years have also seen exciting advances in the chemical and physical characterization of polymer brushes, as well as an ever increasing set of computational and simulation tools that allow understanding and predictions of these surface-grafted polymer architectures. The aim of this contribution is to provide a comprehensive review that critically assesses recent advances in the field and highlights the opportunities and challenges for future work.
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Affiliation(s)
- Justin O Zoppe
- Institut des Matériaux and Institut des Sciences et Ingénierie Chimiques, Laboratoire des Polymères Bâtiment MXD, Ecole Polytechnique Fédérale de Lausanne (EPFL) , Station 12 CH-1015 Lausanne, Switzerland
| | - Nariye Cavusoglu Ataman
- Institut des Matériaux and Institut des Sciences et Ingénierie Chimiques, Laboratoire des Polymères Bâtiment MXD, Ecole Polytechnique Fédérale de Lausanne (EPFL) , Station 12 CH-1015 Lausanne, Switzerland
| | - Piotr Mocny
- Institut des Matériaux and Institut des Sciences et Ingénierie Chimiques, Laboratoire des Polymères Bâtiment MXD, Ecole Polytechnique Fédérale de Lausanne (EPFL) , Station 12 CH-1015 Lausanne, Switzerland
| | - Jian Wang
- Institut des Matériaux and Institut des Sciences et Ingénierie Chimiques, Laboratoire des Polymères Bâtiment MXD, Ecole Polytechnique Fédérale de Lausanne (EPFL) , Station 12 CH-1015 Lausanne, Switzerland
| | - John Moraes
- Institut des Matériaux and Institut des Sciences et Ingénierie Chimiques, Laboratoire des Polymères Bâtiment MXD, Ecole Polytechnique Fédérale de Lausanne (EPFL) , Station 12 CH-1015 Lausanne, Switzerland
| | - Harm-Anton Klok
- Institut des Matériaux and Institut des Sciences et Ingénierie Chimiques, Laboratoire des Polymères Bâtiment MXD, Ecole Polytechnique Fédérale de Lausanne (EPFL) , Station 12 CH-1015 Lausanne, Switzerland
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Venev SV, Potemkin II. Swelling of chemical and physical planar brushes of gradient copolymers in a selective solvent. SOFT MATTER 2014; 10:6442-6450. [PMID: 25058377 DOI: 10.1039/c4sm00723a] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We propose a mean-field theory of chemical and physical planar brushes of linear gradient copolymers swollen in a selective solvent. The polymer chains are grafted to the substrate by the ends with the excess of insoluble monomer units, and the majority of the soluble units are located near the free ends of the chains. The grafting points are considered to be immobile (chemical brush) and mobile in-plane (physical brush). In the latter case the grafting density is determined from the equilibrium conditions (minimum of the free energy). A common peculiarity of the brushes of both types is that the polymer concentration gradually changes from a relatively high value near the substrate (collapsed region of the brush) to a small value near the free surface (swollen region of the brush). In the case of the chemical brush, a polymer depletion zone can appear in the middle of the brush if incompatibility between insoluble and soluble (A and B) units is high enough. Here the polymer density is even lower than near the free surface of the brush. The grafting density of the physical brush is inversely proportional to the chain length and increases with the decrease of the solvent quality for the insoluble (A) units. The latter can be accompanied by shrinkage of the brush thickness due to broad distribution of the insoluble units through the chain: a minor fraction of insoluble units near the free ends can aggregate with a major fraction of them near the substrate. As a result, the concentration of the soluble (B) units can have a maximum in the middle of the brush rather than near the free surface.
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Affiliation(s)
- Sergey V Venev
- Physics Department, Lomonosov Moscow State University, Moscow 119991, Russian Federation.
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Elliott LCC, Jing B, Akgun B, Zhu Y, Bohn PW, Fullerton-Shirey SK. Loading and distribution of a model small molecule drug in poly(N-isopropylacrylamide) brushes: a neutron reflectometry and AFM study. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:3259-3268. [PMID: 23441753 DOI: 10.1021/la305088k] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The structure of a hydrated poly(N-isopropylacrylamide) brush loaded with 5 vol % Isoniazid is studied as a function of temperature using neutron reflectometry (NR) and atomic force microscopy (AFM). NR measurements show that Isoniazid increases the thickness of the brush before, during and after the polymer collapse, and it is retained inside the brush at all measured temperatures. The Isoniazid concentration in the expanded brush is ~14% higher than in the bulk solution, and the concentration nearly doubles in the collapsed polymer, suggesting stronger binding between Isoniazid and the polymer compared to water, even at temperatures below the lower critical solution temperature (LCST) where the polymer is hydrophilic. Typically, additives that bind strongly to the polymer backbone and increase the hydrophilicity of the polymer will delay the onset of the LCST, which is suggested by AFM and NR measurements. The extent of small-molecule loading and distribution throughout a thermo-responsive polymer brush, such as pNIPAAm, will have important consequences for applications such as drug delivery and gating.
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Affiliation(s)
- Lindsay C C Elliott
- Department of Chemistry and Biochemistry, Notre Dame Center for Nano Science and Technology, University of Notre Dame, Notre Dame, Indiana 46556, United States
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Wolff M, Gutfreund P, Rühm A, Akgun B, Zabel H. Nanoscale discontinuities at the boundary of flowing liquids: a look into structure. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2011; 23:184102. [PMID: 21508468 DOI: 10.1088/0953-8984/23/18/184102] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
When downsizing technology, confinement and interface effects become enormously important. Shear imposes additional anisotropy on a liquid. This may induce inhomogeneities, which may have their origin close to the solid interface. For advancing the understanding of flow, information on structures on all length scales and in particular close to the solid interface is indispensable. Neutron scattering offers an excellent tool to contribute in this context. In this work, surface sensitive scattering techniques were used to resolve the structure of liquids under flow in the vicinity of a solid interface. Our results are summarized as follows. First, for a Newtonian liquid we report a depletion distance on the order of nanometers which is far too small to explain the amount of surface slip, on the order of micrometers, found by complementary techniques. Second, for a grafted polymer brush we find no entanglement-disentanglement transition under shear but the grafted film gets ripped off the surface. Third, by evaluating the local structure factor of a micellar solution close to the solid interface it turns out that the degree of order and local relaxation depends critically on the surface energy of the solid surface.
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Affiliation(s)
- Max Wolff
- Department of Physics and Astronomy, Uppsala University, Uppsala 75121, Sweden.
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Griffiths GH, Vorselaars B, Matsen MW. Unit-Cell Approximation for Diblock−Copolymer Brushes Grafted to Spherical Particles. Macromolecules 2011. [DOI: 10.1021/ma2003745] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- G. H. Griffiths
- School of Mathematical and Physical Sciences, University of Reading, Whiteknights, Reading, RG6 6AX, United Kingdom
| | - B. Vorselaars
- School of Mathematical and Physical Sciences, University of Reading, Whiteknights, Reading, RG6 6AX, United Kingdom
| | - M. W. Matsen
- School of Mathematical and Physical Sciences, University of Reading, Whiteknights, Reading, RG6 6AX, United Kingdom
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Guskova OA, Seidel C. Mesoscopic Simulations of Morphological Transitions of Stimuli-Responsive Diblock Copolymer Brushes. Macromolecules 2011. [DOI: 10.1021/ma102349k] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- O. A. Guskova
- Max Planck Institute of Colloids and Interfaces, Science Park Golm, D-14424 Potsdam, Germany
| | - C. Seidel
- Max Planck Institute of Colloids and Interfaces, Science Park Golm, D-14424 Potsdam, Germany
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O’Driscoll BMD, Griffiths GH, Matsen MW, Perrier S, Ladmiral V, Hamley IW. Lateral Phase Separation in Grafted Diblock Copolymer Films. Macromolecules 2010. [DOI: 10.1021/ma101093f] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
| | - Guy H. Griffiths
- Department of Mathematics, University of Reading, Whiteknights, Reading, RG6 6AX, U.K
| | - Mark W. Matsen
- Department of Mathematics, University of Reading, Whiteknights, Reading, RG6 6AX, U.K
| | - Sébastien Perrier
- Key Centre for Polymers and Colloids, School of Chemistry, University of Sydney, NSW, 2006, Australia
| | - Vincent Ladmiral
- Key Centre for Polymers and Colloids, School of Chemistry, University of Sydney, NSW, 2006, Australia
| | - Ian W. Hamley
- Department of Chemistry, University of Reading, Whiteknights, Reading, RG6 6AD, U.K
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