Instability patterns in ultrathin nematic films: comparison between theory and experiment

TL;DR

This paper analyzes the instability patterns in ultrathin nematic films on liquid substrates, deriving analytical expressions for critical parameters and comparing them with experimental data to validate the theoretical model.

Contribution

It provides a continuum elastic theory with analytical formulas for instability thresholds, incorporating surface effects like azimuthal anchoring, and compares predictions with experiments.

Findings

Analytical expressions for critical thickness and wavenumber derived.

Theoretical predictions align with experimental observations.

Surface-like azimuthal anchoring significantly influences instability onset.

Abstract

Motivated by recent experimental observations [U. Delabre et al, Langmuir 24, 3998, 2008] we reconsider an instability of ultrathin nematic films, spread on liquid substrates. Within a continuum elastic theory of liquid crystals, in the harmonic approximation, we find an analytical expressions for the critical thickness as well as for the critical wavenumber, characterizing the onset of instability towards the stripe phase. Comparing theoretical predictions with experimental observations, we establish the utility of surface-like term such as an azimuthal anchoring.