Condensed Matter Theory

Abstract:

We extend a lattice Boltzmann algorithm of liquid crystal hydrodynamics to include an applied electric field. The approach solves the equations of motion written in terms of a tensor order parameter. Back-flow effects and the hydrodynamics of topological defects are included. We investigate some of the dynamics relevant to liquid crystal devices; in particular defect-mediated motion of domain walls relevant to the nucleation of states useful in pi-cells. An anisotropy in the domain wall velocity is seen because defects of different topology couple differently to the flow field.

Abstract:

We use a lattice Boltzmann algorithm for liquid-gas coexistence to investigate the steady-state interface profile of a droplet held between two shearing walls. The algorithm solves the hydrodynamic equations of motion for the system. Partial wetting at the walls is implemented to agree with Cahn theory. This allows us to investigate the processes which lead to the motion of the three-phase contact line. We confirm that the profiles are a function of the capillary number and a finite-size analysis shows the emergence of a dynamic contact angle, which can be defined in a region where the interfacial curvature tends to zero.