Antiferroelectric behavior in a liquid crystalline polymer

Electro-optic and polarization reversal measurements were performed on a side-chain polymer exhibiting a chiral smectic phase. Based on the observed electro-optic and current responses, we discuss the possibility of an antiferroelectric structure in the polymer. In order to establish a model for the observed behavior, a detailed comparison with the properties of the low molar mass antiferroelectric substance MHPOBC was made. The birefringence modulation in the chiral smectic polymer, originating from the field-induced antiferroelectric-to-ferroelectric transition, is analyzed for the case of a randomly oriented sample. The result shows that the coincidence of birefringence modulation and polarization current peaks is strong evidence for the existence of antiferroelectric order in the smectic layers. Such coincidence was observed both for MHPOBC and the chiral side-chain polyacrylate.