Artificial microscopic structures in nematic liquid crystals created by patterned photoalignment and controlled confinement: instrumentation, fabrication and characterization.

摘要

Disclination lines play a decisive role in determining the equilibrium structures of topologically constrained liquid crystal systems including cholesteric blue phases, twist grain boundary phases and liquid crystal colloids. The extra energy associated with disclinations is key to stabilizing one particular director structure over another, yet our knowledge of disclination energetics is limited as are characterization methods. In this work, we detail our approach which has focused onbuilding versatile one-of-a-kind instruments for studying liquid crystal systems. This work details the development and use of two novel instruments: an automated maskless photoalignment pattern generator (maskless system) and ad ynamic-cell system that allows for the automated mechanical adjustment of the liquid crystal cell thickness, twist angle and temperature. Both instruments were extensively refined and characterized for maximum performance. In addition, both instruments were designed as versatile platformsfor new research. In this work, we used the maskless system to create novel surface alignments and Pancharatnam-phase devices, and we employed the dynamic-cell system for the generation and characterization of reverse-twist-domain defect loops.