Dynamics of Director Fluctuations in Confined Liquid Crystals

Abstract

AbstractDynamic light scattering was applied to study the influence of randomness, boundary conditions (planar-axial and homeotropic-radial) and layer thickness (at nanoscale) of 5CB and 8CB confined to cylindrical pores and filled with Aerosil particles on relaxation of director orientational fluctuations. For confined 8CB in the nematic phase two well-defined relaxation processes were observed for both axial and radial orientations of the liquid crystal. The first process is qualitatively associated with bulk-like nematic director fluctuations. The second relaxation process (with slower relaxation time than the first one) is most likely due to the fluctuations in layers nearest the wall surface. The separation between the first and the second (slow) processes is clearer for thinner layers and the amplitude of the slow process is greater for thinner layers. This suggests that the slow process is surface related relaxation. The mode due to relaxation of fluctuations of director orientation in the vicinity of the surface of Aerosil particles was observed in filled liquid crystals as well.