Rotational viscosity in the ferroelectric C* phase - A high pressure study

Abstract

Since the demonstration of microsecond switching using ferroelectric liquid crystals, these materials are considered as key substances for fast electro-optic response, memory effect and other kinds of LCD applications. A basic parameter which decides the speed of electro-optic response is the rotational viscosity γΦ. This property, which is associated with the motion of the molecule around a cone of azimuthal angles is also important in understanding the dynamics of switching. We have performed high pressure studies on a compound exhibiting the ferroelectric-paraelectric (Smectic C*-Smectic A) transition. The results show that the thermal variation of γΦ is of the arrhenius type and its value increases with increasing pressure.