Flying-seed-like liquid crystals

Abstract

In 1911, Vorlärnder reported liquid-crystalline properties of unique “flying-seed-like” alkali metal carboxylates. They are neither “rod-like” nor “disk-like”. Moreover, they have neither a rigid core nor flexible long chains. The molecular shapes are totally different from about 93 000 general liquid crystalline compounds. These flying-seed-like liquid crystals have been forgotten for about 100 years. We revealed and established for the first time from precise microscopic observations and temperature-dependent X-ray diffraction studies that sodium diphenylacetate exhibits a hexagonal columnar mesophase, and that potassium diethylacetate and potassium dimethylacetate exhibit a smectic A mesophase. These “old and new” flying-seed-like liquid crystals will become a novel field of science.