# Partially Disordered Crystal Phases and Glassy Smectic Phases in Liquid Crystal Mixtures

## TL;DR

This study explores how mixing two liquid crystal compounds affects their phase behavior, revealing new disordered and glassy phases.

## Contribution

The paper identifies partially disordered crystal and glassy smectic phases in liquid crystal mixtures.

## Key findings

- Smectic A*, C*, and CA* phases were observed in all mixtures.
- The equimolar mixture showed vitrification of smectic CA* with glass transition properties similar to pure 3F5FPhF6.
- Two mixtures with less 3F5FPhF6 showed partial crystallization to disordered crystal phases.

## Abstract

Three liquid crystalline mixtures were investigated, consisting of compounds abbreviated as MHPOBC and 3F5FPhF6 with molar ratios 0.9:0.1 (MIX5FF6-1), 0.75:0.25 (MIX5FF6-2), and 0.5:0.5 (MIX5FF6-3). The presence of the smectic A*, smectic C*, and smectic CA* phases was observed in all mixtures. The hexatic smectic XA* phase, present in pure MHPOBC, disappeared quickly with an increasing admixture of 3F5FPhF6. Vitrification of smectic CA* was observed for the equimolar mixture, with the glass transition temperature and fragility index comparable to the pure glassforming 3F5FPhF6 component. Partial crystallization to conformationally or orientationally disordered crystal phases was observed on cooling in two mixtures with a smaller fraction of 3F5FPhF6. Broadband dielectric spectroscopy was applied to study the relaxation times in smectic and crystal phases. Vogel–Fulcher–Tammann, Mauro–Yue–Ellison–Gupta–Allan, and critical-like models were applied for analysis of the α-relaxation time in supercooled smectic XA* and smectic CA* phases.