Small amplitude oscillatory shear permeation flow of cholesteric liquid crystal polymers

Abstract

Abstract. We investigate the small amplitude oscillatory shear permeation flow (SAOSPF) of cholesteric liquid crystal polymers (CLCPs) using a mesoscopic model obtained from the Doi kinetic theory for flows of CLCPs. We model the system by Stokes hydrodynamic equations coupled with orientational dynamics and study the frequency-locked solutions of the system by employing a coarsegrained approach. The leading order solutions exhibit boundary layers of thickness of the order of the cholesteric pitch in low frequency regimes but in the order of 1 √ ω in high frequency regimes, where ω is the plate driven frequency. The response of CLCPs has been calculated. Viscoelastic behavior is only observed at intermediate frequencies and the material is essentially viscous at low and high frequency regimes. At both low and high frequencies, the real component of complex viscosity controls its magnitude which is of the order of the reciprocal of the cholesteric pitch at low frequencies while the order of 1 at high frequencies.