Cubic microlattices embedded in nematic liquid crystals: a Landau de-Gennes study

TL;DR

This study uses a Landau-de Gennes model to analyze cubic microlattices in nematic liquid crystals, deriving effective energies and convergence rates, and showing how surface anchoring influences phase transitions and particle alignment.

Contribution

It provides a homogenised limit analysis for cubic lattice embedded nematic systems, including effects of surface anchoring and symmetry loss, with explicit convergence rate results.

Findings

Effective free energy can be tuned via surface anchoring parameters.

Homogenised limit captures changes in particle alignment due to symmetry loss.

Convergence rates for surface energies and minimisers are established.

Abstract

We consider a Landau-de Gennes model for a connected cubic lattice scaffold in a nematic host, in a dilute regime. We analyse the homogenised limit for both cases in which the lattice of embedded particles presents or not cubic symmetry and then we compute the free effective energy of the composite material. In the cubic symmetry case, we impose different types of surface anchoring energy densities, such as quartic, Rapini-Papoular or more general versions, and, in this case, we show that we can tune any coefficient from the corresponding bulk potential, especially the phase transition temperature. In the case with loss of cubic symmetry, we prove similar results in which the effective free energy functional has now an additional term, which describes a change in the preferred alignment of the liquid crystal particles inside the domain. Moreover, we compute the rate of convergence for how fast the surface energies converge to the homogenised one and also for how fast the minimisers of the free energies tend to the minimiser of the homogenised free energy.