Synthesis of polyphilic compounds Evidence for ferroelectricity in a non-chiral mesophase

The synthesis and properties of new mesomorphic ferroelectrics composed of nonchiral polyphilic molecules are described. Polyphilic molecular units are made up of a sequence of chemical fragments differing by their chemical nature. The segregation between unlike species is used to favour a polar packing. Ferroelectricity is demonstrated by the measurement of an acoustically induced piezoelectric response and the determination of repolarization currents. It is the first time that a ferroelectric repolarizable mesophase is obtained with non-chiral molecular units. The mechanism of ferroelectricity is therefore different from that found in conventional chiral smectic C.