Entropically driven reentrant SmC-SmA-SmC phase transition in composite polymer--liquid crystal systems

TL;DR

This paper investigates how polymers influence the phase behavior of liquid crystals, revealing an entropically driven reentrant SmC-SmA-SmC phase transition due to polymer confinement effects.

Contribution

It introduces a model explaining the reentrant phase transition in polymer-liquid crystal composites based on entropy-energy considerations.

Findings

Polymers induce a reentrant SmC phase around the SmA phase.

The phase diagram shape is predicted by simple entropy-energy arguments.

Reentrant behavior occurs when polymers are confined between smectic layers.

Abstract

I consider the effects of polymers on the smectic phase of a host liquid crystal matrix. Focusing on the regime in which the polymers are predominately confined between the smectic layers, I find that the presence of the polymers can lead to a reentrant phase diagram with the smectic-C sandwiching the smectic-A phase from both the high and low temperature sides. Simple entropy-energy arguments predict the shape of the reentrant phase boundary.