scholarly journals A Kinetic Method for Investigating the Structure of Adsorbed Polymer Layers

1996 ◽  
Vol 14 (4) ◽  
pp. 251-257 ◽  
Author(s):  
S. Minko ◽  
I. Luzinov ◽  
I. Evchuk ◽  
S. Voronov
Keyword(s):  
Induction Period ◽  
Layer Structure ◽  
Critical Concentration ◽  
Kinetic Method ◽  
Adsorbed Layer ◽  
Polymer Chains ◽  
The Poor ◽  
Adsorbed Polymer ◽  
Zno Powder ◽  
Conformation Transition

A kinetic method for investigating the adsorbed layer structure of a polymer (the copolymer of styrene and maleic anhydride) on a ZnO powder surface was developed, the method is based on the model of the heterogeneously inhibited polymerization of styrene ‘filled’ with ZnO powder. The polymerization is preceded by an induction period. The length of this period depends on the concentration of inhibiting sites (n) on the surface of ZnO. The adsorbed polymer blocks such inhibiting sites and the induction period decreases. This model was used to estimate n. A peak was observed in the experimental relationship connecting n with the amount adsorbed. This peak was interpreted as the critical concentration for conformation transition brought about by the interaction of the polymer chains at the surface. Below this concentration adsorbed macromolecules are considered as isolated chains at the surface. This state is characterized by the poor mobility of segments.

scholarly journals RuSseL: A Self-Consistent Field Theory Code for Inhomogeneous Polymer Interphases

Computation ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 57
Author(s):  
Constantinos J. Revelas ◽  
Aristotelis P. Sgouros ◽  
Apostolos T. Lakkas ◽  
Doros N. Theodorou
Keyword(s):  
Field Theory ◽  
Polymer Melt ◽  
Polymer Chains ◽  
Solid Polymer ◽  
One Dimensional ◽  
Consistent Field ◽  
Adsorbed Polymer ◽  
Self Consistent ◽  
Self Consistent Field ◽  
Self Consistent Field Theory

In this article, we publish the one-dimensional version of our in-house code, RuSseL, which has been developed to address polymeric interfaces through Self-Consistent Field calculations. RuSseL can be used for a wide variety of systems in planar and spherical geometries, such as free films, cavities, adsorbed polymer films, polymer-grafted surfaces, and nanoparticles in melt and vacuum phases. The code includes a wide variety of functional potentials for the description of solid–polymer interactions, allowing the user to tune the density profiles and the degree of wetting by the polymer melt. Based on the solution of the Edwards diffusion equation, the equilibrium structural properties and thermodynamics of polymer melts in contact with solid or gas surfaces can be described. We have extended the formulation of Schmid to investigate systems comprising polymer chains, which are chemically grafted on the solid surfaces. We present important details concerning the iterative scheme required to equilibrate the self-consistent field and provide a thorough description of the code. This article will serve as a technical reference for our works addressing one-dimensional polymer interphases with Self-Consistent Field theory. It has been prepared as a guide to anyone who wishes to reproduce our calculations. To this end, we discuss the current possibilities of the code, its performance, and some thoughts for future extensions.

Shear-induced stretching of adsorbed polymer chains

Soft Matter ◽  
2009 ◽  
Vol 5 (16) ◽  
pp. 3014 ◽  
Author(s):  
Gui-Li He ◽  
René Messina ◽  
Hartmut Löwen ◽  
Anton Kiriy ◽  
Vera Bocharova ◽  
...  
Keyword(s):  
Polymer Chains ◽  
Adsorbed Polymer

Conformational behavior of short adsorbed polymer chains

1999 ◽  
Vol 35 (1) ◽  
pp. 167-172 ◽  
Author(s):  
Linxi Zhang ◽  
Xianghong Wang ◽  
Haizhu Ma ◽  
Youxing Huang
Keyword(s):  
Polymer Chains ◽  
Conformational Behavior ◽  
Adsorbed Polymer

Effect of Acid–Base Interactions on Conformation of Adsorbed Polymer Chains

2015 ◽  
Vol 5 (1) ◽  
pp. 45-49 ◽  
Author(s):  
He Zhu ◽  
Nishad Dhopatkar ◽  
Ali Dhinojwala
Keyword(s):  
Polymer Chains ◽  
Acid Base ◽  
Adsorbed Polymer

Theory of the stabilization of colloids by adsorbed polymer

1974 ◽  
Vol 337 (1611) ◽  
pp. 509-516 ◽  
Keyword(s):  
Plane Surface ◽  
Analytic Form ◽  
Polymer Chains ◽  
Contour Length ◽  
Link Length ◽  
Excluded Volume Effects ◽  
Adsorbed Polymer ◽  
Random Flight ◽  
The Stability ◽  
Simple Analytic Form

The configurational free energy of random flight polymer chains adsorbed by one end onto a plane surface as a function of the distance from a parallel plane surface is expressed to a good approximation in simple analytic form. The result is used to discuss the stabilization of a colloid suspension by adsorbed polymer. According to this theory two types of aggregation of colloid particles may occur. If LI < AS/2π 3 NkT , where l is the link length and L the contour length of a polymer chain, A is the Hamaker constant, N /S is the number of adsorbed polymer chains per unit area and kT is the Boltzman constant multiplied by temperature, the particles adhere closely, but if AS/2π 3 kT < IL < AS/nkT lg 2N a looser association is formed. It is expected that the presence of excluded volume effects would greatly increase the stability against the looser association.

The effect of excluded volume on polymer dispersant action

1975 ◽  
Vol 343 (1635) ◽  
pp. 427-442 ◽  
Keyword(s):  
Free Energy ◽  
High Surface ◽  
Volume Effect ◽  
Polymer Chains ◽  
Excluded Volume ◽  
Density Distributions ◽  
Excluded Volume Effects ◽  
Adsorbed Polymer ◽  
Polymer Distribution ◽  
Dimensional Equation

Polymer-stabilized colloid particles are modelled theoretically by plane surfaces on to which polymer chains are adsorbed by one end only. Interactions between segments of the polymer are treated as an excluded volume effect. It is shown that for high surface densities the polymer distribution function exactly satisfies a one dimensional equation which is solved numerically for two values of excluded volume to give the polymer segment density distributions and the free energy of interaction for various separations of the plane surfaces. It is found that a positive value of excluded volume greatly increases the repulsive free energy compared with that for chains with zero excluded volume, particularly at large separation distances of the surfaces. Excluded volume effects must therefore play an important part in the stabilization of colloids by adsorbed polymer.

scholarly journals Efficient encapsulation of proteins with random copolymers

2018 ◽  
Vol 115 (26) ◽  
pp. 6578-6583 ◽  
Author(s):  
Trung Dac Nguyen ◽  
Baofu Qiao ◽  
Monica Olvera de la Cruz
Keyword(s):  
Enzymatic Activity ◽  
Average Distance ◽  
Aqueous Media ◽  
Adsorbed Layer ◽  
Computational Design ◽  
Polymer Chains ◽  
Disordered Proteins ◽  
Random Copolymers ◽  
Adsorption Sites

Membraneless organelles are aggregates of disordered proteins that form spontaneously to promote specific cellular functions in vivo. The possibility of synthesizing membraneless organelles out of cells will therefore enable fabrication of protein-based materials with functions inherent to biological matter. Since random copolymers contain various compositions and sequences of solvophobic and solvophilic groups, they are expected to function in nonbiological media similarly to a set of disordered proteins in membraneless organelles. Interestingly, the internal environment of these organelles has been noted to behave more like an organic solvent than like water. Therefore, an adsorbed layer of random copolymers that mimics the function of disordered proteins could, in principle, protect and enhance the proteins’ enzymatic activity even in organic solvents, which are ideal when the products and/or the reactants have limited solubility in aqueous media. Here, we demonstrate via multiscale simulations that random copolymers efficiently incorporate proteins into different solvents with the potential to optimize their enzymatic activity. We investigate the key factors that govern the ability of random copolymers to encapsulate proteins, including the adsorption energy, copolymer average composition, and solvent selectivity. The adsorbed polymer chains have remarkably similar sequences, indicating that the proteins are able to select certain sequences that best reduce their exposure to the solvent. We also find that the protein surface coverage decreases when the fluctuation in the average distance between the protein adsorption sites increases. The results herein set the stage for computational design of random copolymers for stabilizing and delivering proteins across multiple media.

Control of Persistent Nonequilibrium Adsorbed Polymer Layer Structure by Transient Exposure to Surfactants

Langmuir ◽  
2003 ◽  
Vol 19 (7) ◽  
pp. 2736-2744 ◽  
Author(s):  
Alan D. Braem ◽  
Simon Biggs ◽  
Dennis C. Prieve ◽  
Robert D. Tilton
Keyword(s):  
Layer Structure ◽  
Polymer Layer ◽  
Adsorbed Polymer

Investigation of Polymer Brushes and Adsorbed Layers under Shear

1997 ◽  
Vol 30 (5) ◽  
pp. 680-683 ◽  
Author(s):  
D. Nguyen ◽  
C. J. Clarke ◽  
A. Eisenberg ◽  
M. H. Rafailovich ◽  
J. Sokolov ◽  
...  
Keyword(s):  
Shear Rate ◽  
Polymer Brushes ◽  
Adsorbed Layer ◽  
Random Copolymer ◽  
Neutron Reflectometry ◽  
Recent Theory ◽  
Observable Effect ◽  
Density Profiles ◽  
Adsorbed Polymer ◽  
Adsorbed Layers

Neutron reflectometry was used to investigate the density profiles of polymer brushes and an adsorbed polymer layer under shear. The brushes consisted of end-functionalized deuterated polystyrene. The adsorbed polymer was a random copolymer of deuterated styrene and 4-vinylpyridine. The brush and the adsorbed layer were sheared by the flowing of solvents over the polymer, with a maximum shear rate of 104s−1. Density profiles of the brush and the layer were determined before, during and after shear. The shear had no observable effect on the polymer profiles in any of the experiments. We discuss these results in the context of other experiments and a recent theory.

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