The Phase Behaviors of A Polymer Solution Confined between Two Concentric Cylinders

TL;DR

This paper theoretically investigates the phase behaviors of a polymer solution confined between coaxial cylinders, revealing confinement-independent spinodal points and the formation of periodic concentration patterns influenced by boundary properties.

Contribution

It introduces a combined analysis using Gaussian fluctuation theory and self-consistent mean-field theory to understand phase separation and pattern formation in cylindrical confinement.

Findings

Spinodal point is confinement-independent due to free dimension.

Fluctuation modes include axial plane waves leading to periodic patterns.

Wetting phenomena influence phase separation based on wall properties.

Abstract

A theoretical study on the phase behaviors of a polymer solution confined between two coaxial cylindrical walls is presented. For the case of a neutral inner cylinder, the spinodal point derived through the Gaussian fluctuation theory is confinement-independent because of the existence of a free dimension in the system. The kinetic analysis indicates that the fluctuation modes always have a component of a plane wave along the axial direction, which can lead to the formation of a periodic-like concentration pattern. On the other hand, the equilibrium structure of the system is obtained by using the self-consistent mean-field theory (SCMFT) and the interplay between the "wetting" phenomenon and the phase separation is observed by modifying the property of the inner cylinderical wall.