Dynamic light scattering studies of cholesteric and polymer-stabilized cholesteric liquid crystals

Dynamic light scattering of pure cholesteric and polymer-stabilized cholesteric liquid crystals shows two relaxation modes: twist and viscous-splay (umbrella). The twist mode is diffusive, whereas the frequency associated with the viscous-splay deformation goes to a constant at zero scattering angle. In the presence of polymer networks the frequency corresponding to the twist deformation decreases as a result of an increase in the viscosity, but the frequency associated with the viscous-splay deformation increases. This is attributed to the breakup of cholesteric domains by the polymer network. © 1998 The American Physical Society.