Organic-Inorganic Hybrid Liquid Crystal: Iinduction of Thermotropic Liquid-Crystallinity to Monodispersed Iron Oxide Nanoparticles by the Specific Adsorption of Organic Phosphates

Abstract

Monodispersed hematite fine particles with spindle, cuboidal, and platelet shapes have been prepared by the Gel-Sol method, which is a particle synthesis technique in condensed system. Hybridization of the monodispersed hematite fine particles with calamitic liquid-crystalline organic phosphates enabled us to obtain a novel-type of organic-inorganic hybrid thermotropic liquid crystals (LCs). It is revealed that the key for the hybridization is the specific adsorption of the phosphate group to the surfaces parallel to the c-axis of the hematite particles. The hybrid LC shows thermotropic nematic or cubic liquid-crystallinity in wide ranges of temperatures. Variable-temperature small angle X-ray measurements reveal that the spontaneous formation of periodic structure by the hybridization induces the thermotropic liquid crystallinity.