Role of structural biaxiality on the phase behaviour of chiral liquid crystals

TL;DR

This study uses computer simulations to explore how molecular biaxiality influences phase behavior in chiral liquid crystals, revealing effects on phase types, domain structures, and pitch length relevant for optical applications.

Contribution

It demonstrates how molecular biaxiality and chirality jointly affect phase formation and structure in chiral liquid crystals through coarse-grained molecular dynamics simulations.

Findings

Biaxial molecules favor cholesteric phase formation.

Higher chirality leads to twisted cylindrical domains with elliptical cross-sections.

Cholesteric pitch decreases with increasing chirality and biaxiality.

Abstract

We report a computer simulation study on the effect of molecular structural biaxiality in the phase formation of chiral molecules. In this study, we have done coarse-grained modeling to observe self-assembled phase behavior. In our molecular dynamics simulation study we varied both the chiral interaction strength and molecular biaxiality. Uniaxial molecules give rise to cholesteric phase, blue phase whereas molecular biaxiality favours cholesteric phase. At higher chirality, small chiral domains are formed creating twisted cylindrical networks with each cylinder having elliptical cross-sections instead of circular nature as found in uniaxial systems. The value of cholesteric pitch decreases when chirality and molecular biaxiality becomes higher. Coaction of biaxiality and chirality is crucial for fabricating liquid crystal materials with optical properties suitable for displays, sensors and chiral photonic devices.