Texture Formation in Multiphase Polymer-Liquid Crystal Materials

Texture formation in a binary mixture of a flexible polymer and a liquid crystal has been studied using a nonlocal kinetic model for phase separation in the presence of liquid crystalline order. The model takes into account couplings between phase separation, phase ordering, and texture formation. The phase separation-phase ordering coupling leads to orientation normal to local concentration gradients, while curvature in the isotropic phase leads to defect nucleation in the nematic phase. The phase separation and phase ordering process is characterized by simulating quenches into unstable and metastable regions of the phase diagram. Emerging twodimensional morphologies include nematic emulsions and filled nematics. Droplets in nematic emulsions display the classical bipolar director field. The director field in filled nematics displays a stable defect polygonal network. Correlations between defect density and bi-phasic geometry are established and characterized using topological rules for liquid crystal defects.