Generation of Axially Polar Ferroelectricity in a Columnar Liquid Crystal Phase by Introducing Chirality

Abstract

AbstractAxially polar ferroelectric columnar liquid crystals (AP‐FCLCs) are materials in which the molecules are self‐organized into axially polar columns and exhibit switching and holding of their polar directions. If the polar directions along the columnar axis can be controlled by using a nanosized electrode, AP‐FCLCs have the potential to realize ultrahigh‐density memory devices. Though switching polarities in columnar liquid crystal phases have been studied by many scientists, it remains difficult to realize bistable switching. In this study, it is found that replacement of the normal alkyl groups (decyl groups) with chiral groups ((S)‐citronellyl groups) in an N,N’‐bis(3,4,5‐trialkoxyphenyl)urea realizes perfect ferroelectricity in the rectangular columnar liquid crystal phase, and it is confirmed that the phase is an AP‐FCLC phase. The differences in the properties and molecular packing structures between the achiral and chiral urea compounds are investigated. Furthermore, the mechanism for achieving ferroelectricity by introduction of the chiral alkyl chains is postulated.