Confinement effects at the transition from a chiral fluid SmC* to a hexatic SmI*liquid crystal phase

Abstract

The temperature dependence of the spontaneous polarization across the phasetransition from the fluid smectic C* to the hexatic smectic I* phase of achiral liquid crystal was investigated with respect to confinement effects,due to closely spaced substrates. A strong thickness dependence of thepolarization was observed in both the SmC* and SmI* phases, which cannot beinterpreted either by polarization screening due to ionic impurities, or bythe polarization self-screening model. A possible explanation is given interms of non-switching interface regions close to the substrates, caused bystrong anchoring conditions. It is demonstrated that the occurrence ofbond-orientational order does not affect the anchoring behaviour of the liquidcrystal. Confinement effects were observed for decreasing cell gap below 4 μm, while the first order character of theSmC*–SmI* phase transition is retained.