Transitions between paraelectric and ferroelectric phases of bent-core smectic liquid crystals in the bulk and in thin freely suspended films

摘要

We report on the contrasting phase behavior of a bent-core liquid crystal with a large opening angle betweennthe mesogenic units in the bulk and in freely suspended films. Second-harmonic generation experiments andndirect observation of director inversion walls in films in an applied electric field reveal that the nonpolar smecticnC phase observed in bulk samples becomes a ferroelectric “banana” phase in films, showing that a mesogen withna small steric moment can give a phase with polar order in freely suspended films even when the correspondingnbulk phase is paraelectric.