Domain structure in nematic liquid crystals

摘要

Domain structure plays an important role in mechanical properties of materials In some cases typical linear domain size can be effectively controlled by adding a perturber (impurity) to the system. To demonstrate this we study the domain evolution of the system using the Brownian molecular dynamics and the Lebwohl-Lasher lattice model. This minimal model well describes the main universal features of the coarsening dynamics following a sudden temperature or pressure driven phase transition from the orientationally disordered to ordered phase. A typical corresponding condensed matter system is the isotropic-nematic phase transition in liquid crystals or in an ensemble of nanorods. We calculate the saturated domain size as a function of impurity concentration, which acts as the random anisotropy field.