Creation of Electrically and Optically Functional Materials from Cellulose Derivatives via Simple Modification and Orientation Control

Abstract

The authors demonstrate a series of investigations that led to the creation of functional materials from cellulose derivatives (cellulose acetate (CA), cyanoethyl cellulose (CyEC), and ethyl cellulose (EC)), which have relatively simple structures and are supposed to be practical for industrial use. For these derivatives, we performed molecular modification with introducing simple substituent or combining with different polymers, applied processing with deformation, and controlled the orientation behavior of molecular chains and segments, in order to create electrical and optical functional materials. As an optical function, we established the design guidelines for CA-based materials that can precisely control the optical anisotropy including zero birefringence. As an electrical function, we obtained a CyEC-based material showing the largest dielectric constant among thermally stable organic polymers. Very recently, we have proposed a dual mechanochromism in which by mechanical stimulus, not only the cholesteric color changes, but also the polarity of the selectively reflected circularly polarized light is reversed, utilizing the inherent cholesteric liquid crystallinity of EC.