Entropic Unmixing in Nematic Blends of Semiflexible Polymers

TL;DR

This paper investigates phase separation in nematic blends of semiflexible polymers, revealing entropic unmixing driven by differences in local bond angles, using simulations and theoretical analysis.

Contribution

It introduces a novel entropic unmixing mechanism in nematic polymer blends driven by local bond angle preferences, without attractive interactions.

Findings

Phase diagrams with triple and critical points predicted.

Unmixing driven solely by entropy and bond angle differences.

Molecular Dynamics and Density Functional Theory used for predictions.

Abstract

Binary mixtures of semiflexible polymers with the same chain length but different persistence lengths separate into two coexisting different nematic phases when the osmotic pressure of the lyotropic solution is varied. Molecular Dynamics simulations and Density Functional Theory predict phase diagrams either with a triple point, where the isotropic phase coexists with two nematic phases, or a critical point of unmixing within the nematic mixture. The difference in locally preferred bond angles between the constituents drives this unmixing without any attractive interactions between monomers.