Non-Isothermal Model for Nematic Spherulite Growth

TL;DR

This study models the growth of nematic spherulites in an isotropic phase, incorporating thermal effects and anisotropy, and predicts growth laws consistent with experimental data using a Landau-de Gennes framework.

Contribution

It introduces a thermal energy balance into a Landau-de Gennes model to accurately predict spherulite growth regimes and transitions.

Findings

Thermal effects influence growth law exponents.

Transition from volume-driven to thermally limited growth observed.

Model aligns well with experimental growth behavior.

Abstract

A computational study of the growth of two-dimensional nematic spherulites in an isotropic phase was performed using a Landau-de Gennes type quadrupolar ensor order parameter model for the first-order isotropic/nematic transition of 5CB (pentyl-cyanobiphenyl). An energy balance, taking anisotropy into account, was derived and incorporated into the time-dependent model. Growth laws were determined for two different spherulite morphologies of the form tn, with and without the inclusion of thermal effects. Results show that incorporation of the thermal energy balance correctly predicts the transition of the growth law exponent from the volume driven regime (n=1) to the thermally limited regime (approaching n=0.5), agreeing well with experimental observations. An interfacial nemato-dynamic model is used to gain insight into the interactions that result in the progression of different spherulite growth regimes.