Surface anchoring on layers of grafted liquid-crystalline chain molecules: A computer simulation

TL;DR

This study uses Monte Carlo simulations to investigate how grafted liquid-crystalline chains influence the orientation of nematic liquid crystals, revealing a first-order transition from planar to tilted alignment as grafting density increases.

Contribution

It demonstrates that grafted liquid-crystalline chains can induce a controllable tilt in nematic fluids, showing a first-order transition and a wide range of accessible anchoring angles.

Findings

First-order transition from planar to tilted alignment with increasing grafting density

Continuous decrease in tilt angle beyond the transition

Large range of accessible anchoring angles

Abstract

By Monte Carlo simulations of a soft ellipsoid model for liquid crystals, we study whether a layer of grafted liquid-crystalline chain molecules can induce tilt in a nematic fluid. The chains are fairly short (four monomers) and made of the same particles as the solvent. They are attached to a substrate which favors parallel (planar) alignment. At low grafting densities, the substrate dominates and we observe planar alignment. On increasing the grafting density, we find a first order transition from planar to tilted alignment. Beyond the transition, the tilt angle with respect to the surface normal decreases continuously. The range of accessible anchoring angles is quite large.