Amphiphilic polymer brush in a mixture of incompatible liquids

Birshtein, T.M.; Zhulina, Ekaterina B.; Mercurieva, Anna A.

doi:10.1002/(sici)1521-3919(20000101)9:1<47::aid-mats47>3.0.co;2-j

Cited by 9 publications

(2 citation statements)

References 8 publications

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“…The transition between collapsed and swollen states was analogous to that in a single-component solvent with changes in temperature or solvent quality. Later, Birshtein et al 35 considered solvents that had low mutual solubility. They found that the brush exhibited a first-order compositional transition characterized by spontaneous increase in height and adsorption of a good solvent.…”

Section: Introductionmentioning

confidence: 99%

“…The authors also examined a conformational transition induced by an external deformation of the brush. 35,37 Lyatskaya and Balasch 34 considered by SCFT water sorption from oil−water mixture by dense hydrophilic brushes including a weakly acidic polymer that was allowed to dissociate. The water concentration in the mixture was shown to control the effective brush height, and the local density of polymer segments has a maximum at the interface that formed between the hydrophilic layer that consisted of water and hydrophilic polymer and the hydrophobic oil bulk.…”

Section: Introductionmentioning

confidence: 99%

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Morphological Transformations in Polymer Brushes in Binary Mixtures: DPD Study

2014

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Morphological transformations in polymer brushes in a binary mixture of good and bad solvents are studied using dissipative particle dynamics simulations drawing on a characteristic example of polyisoprene natural rubber in an acetone-benzene mixture. A coarse-grained DPD model of this system is built based on the experimental data in the literature. We focus on the transformation of dense, collapsed brush in bad solvent (acetone) to expanded brush solvated in good solvent (benzene) as the concentration of benzene increases. Compared to a sharp globule-to-coil transition observed in individual tethered chains, the collapsed-to-expanded transformation in brushes is found to be gradual without a prominent transition point. The transformation becomes more leveled as the brush density increases. At low densities, the collapsed brush is highly inhomogeneous and patterned into bunches composed of neighboring chains due to favorable polymer-polymer interaction. At high densities, the brush is expanded even in bad solvent due to steric restrictions. In addition, we considered a model system similar to the PINR-acetone-benzene system, but with the interactions between the solvent components worsened to the limit of miscibility. Enhanced contrast between good and bad solvents facilitates absorption of the good solvent by the brush, shifting the collapsed-to-expanded transformation to lower concentrations of good solvent. This effect is especially pronounced for higher brush densities.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Morphological Transformations in Polymer Brushes in Binary Mixtures: DPD Study

2014

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SCF Theory of a Polymer Brush Immersed into a Multi‐Component Solvent

Amoskov

Birshtein

Mercurieva

2005

Macro Theory & Simulations

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Summary: Self‐consistent field (SCF) theory is developed for a polymer brush immersed into a multi‐component solvent. Thermodynamics of the plane inhomogeneous brush is mainly determined by thermodynamics of the basic system, i.e., a homogeneous solution of a polymer dissolved in a multi‐component solvent that is in partial (or membrane) equilibrium with a bulk. Binary solvent with partially miscible components is in the focus of this investigation. The peculiarities of the brush are studied on the basis of the phase diagrams constructed for the basic system. Non‐trivial effects are demonstrated: microphase segregation of the brush and collapse of the brush under its filling with a good solvent in a pre‐binodal region of the bulk mixed solvent. Mathematical apparatus is developed and allows obtaining phase diagrams, density profiles, and other characteristics of the system under consideration.

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Effect of a Polymer Brush on Capillary Condensation

et al. 2001

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We consider colloidal particles in a binary solvent. The solvent mixture has a solubility gap. The system is studied, from a solvent point of view, in the one-phase region near the binodal. The colloidal stability is significantly influenced by a mechanism called capillary condensation. In the confined space between particles, the minority solvent can form a solvent bridge resulting in an attractive force. This occurs when the particles prefer the minority solvent over the majority one. One way to protect such particles from capillary condensation flocculation is to end-graft polymers onto them. The main solvent should then be the better solvent for the polymer. However, if the chains are amphiphilic, in the sense that they have similar affinity for both solvents, it is possible to create conditions such that the colloidal particles are only kinetically stabilized by the brush chains. The true thermodynamic equilibrium may be the flocculated state, where two particles are held together by a thin minority-liquid film. This state can be reached only when a repulsive barrier, due to the compression of a polymer brush, is overcome. The opposite case also exists. It is possible that the global minimum is the dispersed one, and the particles are held together by a metastable film of the minority solvent. Now, the separation of the particles is retarded by the work of formation of two polar−apolar interfaces. These scenarios were proven by self-consistent-field calculations of the Scheutjens−Fleer type.

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Amphiphilic polymer brush in a mixture of incompatible liquids

Cited by 9 publications

References 8 publications

Morphological Transformations in Polymer Brushes in Binary Mixtures: DPD Study

Morphological Transformations in Polymer Brushes in Binary Mixtures: DPD Study

SCF Theory of a Polymer Brush Immersed into a Multi‐Component Solvent

Effect of a Polymer Brush on Capillary Condensation

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