COMPUTER SIMULATION OF THE HOMEOTROPIC TO FOCAL CONIC TRANSITION IN CHOLESTERICS

Abstract

Previous reports have proposed mechanisms for the homeotropic to focal conic transition in cholesterics. In this report, we present quantitative numerical modeling of this transition. We will show that the simulation shows the existence of the transient planar state, agreeing with previous experimental findings. We will also demonstrate that the simulations never show energy densities high enough to form isotropic regions, demonstrating that this transition is a continuous process. Instead of introducing isotropic regions, the system transforms through an undulation distortion which strongly resembles a Helfrich-Hurault distortion. This simulation is compared with two experimental samples: one with parallel boundary conditions and one with perpendicular boundary conditions. The simulations are compared with dynamical capacitive measurements and microscope photographs, and found to agree very well. We will present detailed drawings of the director configuration during this transition. The agreement of this simulation with the experimental data shows that the mechanism of this transition is now well understood