Some Observations on the Sense and Magnitude of Spontaneous Polarization and Twisting Power of a Number of Ferroelectric Liquid Crystal Types

Abstract

The sense and magnitude of spontaneous polarization of a number of ferroelectric liquid crystal types were measured. Compounds with a polar group close to the chiral center showed large Ps values, amounting to 150 nC/cm² in the highest case. The alteration of signs of Ps as the chiral center is moved stepwise from the central core in the series of compounds having an alkyl or alkoxy wing chain was examined. Compounds in which the chiral center is connected to the core by an ether linkage showed singularity. The well-known SED-ROD and SOL-REL rule for cholesterics applied to almost all the diverse types of compounds of the present study also in the S*_c phase.

Key Words:

• ferroelectric liquid crystal
• spontaneous polarization
• chirality
• cholesteric phase