Monte Carlo simulations of liquid crystals near rough walls

TL;DR

This study uses Monte Carlo simulations to investigate how surface roughness affects the structure and anchoring properties of liquid crystals near solid substrates, revealing that increased roughness reduces order and anchoring strength.

Contribution

It introduces a simulation approach to quantify the impact of surface roughness on liquid crystal alignment and anchoring at solid interfaces.

Findings

Density and order decrease with surface roughness.

Anchoring strength diminishes as roughness increases.

Surface roughness influences liquid crystal alignment near walls.

Abstract

The effect of surface roughness on the structure of liquid crystalline fluids near solid substrates is studied by Monte Carlo simulations. The liquid crystal is modelled as a fluid of soft ellipsoidal molecules and the substrate is modelled as a hard wall that excludes the centres of mass of the fluid molecules. Surface roughness is introduced by embedding a number of molecules with random positions and orientations within the wall. It is found that the density and order near the wall are reduced as the wall becomes rougher (i.e. the number of embedded molecules is increased). Anchoring coefficients are determined from fluctuations in the reciprocal space order tensor. It is found that the anchoring strength decreases with increasing surface roughness.