Hydrodynamical modes and light scattering in the liquid-crystalline cubic blue phases. II. Dynamic theory

Publisher Website
Google Scholar
Abstract
As shown in the preceding paper, the hydrodynamical modes of the cubic blue phases are displacement modes, which are equivalent to acoustic phonons in crystal. We apply the model of a viscoelastic mixture to describe their dynamics. For the transverse modes the dispersion relations do not show the expected power-law behavior of the hydrodynamical regime. Instead they display a flat, widely extended minimum that explains the strange dynamics of light-scattering experiments in cubic blue phases. Within the kinematical theory of light scattering we propose special geometries for measuring the material parameters of the viscoelastic mixture. To understand the forescattering, commonly observed in experiments, and the strong dependence of the fluctuating light intensity on the incident wavelength, we extend our calculation to the more general dynamical theory. A qualitative interpretation of the experiments suggests that the cubic blue phases are highly anisotropic with regard to their viscous behavior.

This publication has 21 references indexed in Scilit: