Multiblock Copolymer Solutions in Contact with a Surface: Self-Assembly, Adsorption, and Percolation

Abstract

Amphiphilic copolymers are often used as compatibilizing or stabilizing agents, either in solution or at surfaces. In the special case of multiblock copolymers the connectivity of the blocks combines with the antagonistic behavior of the different types of blocks. Here we report on the behavior of solutions of amphiphilic multiblock copolymers with a large number of blocks and a low fraction of solvophobic monomers in contact with an attractive surface. Using lattice Monte Carlo simulations, the influence on the structures of the solvent quality and the type of surface from noninteracting to strongly attractive to the solvophobic monomers can be assessed. In the presence of a surface bulk micelles are formed that are not different in size and shape from the micelles observed in the absence of a surface. When increasing the surface attraction, solvophobic monomers tend to adsorb either as isolated blocks or forming surface micelles. Evidence is given of a surface concentration threshold above which surface micelles can form due to microphase separation. These surface micelles are in equilibrium with bulk micelles, some of which are connected to the surface through a path of either hydrophobic and/or hydrophilic blocks or hydrophobic cross-links, or both. The size distributions of bulk and connected micelles are similar. With increasing surface concentration surface micelles get organized due to the steric repulsion between core-shell surface micelles. Moreover, these organized surface micelles percolate. The connected micelles form a concentrated layer parallel to the attractive surface. In addition, these systems are governed by two very different time scales: The fast one leads to micellar self-assembly in the bulk and at the surface while the slow one prevents the system from reaching equilibrium in the course of the simulations and corresponds to the transfer of copolymers from the bulk to the attractive surface.

Interaction Forces between Supported Lipid Bilayers in the Presence of PEGylated Polymers

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Computer Study of Chromatographic Separation Process: A Monte Carlo Study of H-Shaped and Linear Homopolymers in Good Solvent

“…They have been successfully used for the solution of a number of topics in almost all fields of polymer science. The number of simulation papers is very high, and it is why we included only several interesting papers published recently − to demonstrate progress in this field and further we focus only on articles devoted directly to the studied topic. The behavior of various polymer chains close to planar surfaces, in narrow slits and in the pores, and the mechanism of the chromatographic separation of polymer chains have already been studied theoretically − by scaling approaches, , by mean-field calculations, − and particularly by lattice Monte Carlo (MC) simulations. − A number of individual studies concerning the effects of chain architecture , and flexibility, , molar mass, polymer concentration, , solvent quality, temperature, , polymer–wall interaction, ,, and smoothness versus roughness of the surface have been published recently.…”

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“…In more concentrated solutions, decreasing the quality of the solvent and increasing the concentration of polymers gives rise to different structural regimes, from a homogeneous solution to a percolating network of core-shell micelles [29] (see Fig. 5), which can be in equilibrium with a 2D percolating network of micelles when the solution is in contact with a hydrophobic surface [30] (see Fig. 4a).…”