LIQUID-CRYSTALLINE POLYIMIDES .20. PHOTOREACTIVE AND CHOLESTERIC POLY(ESTER-IMIDE)S BASED ON 4-AMINOCINNAMIC ACID TRIMELLITIMIDE AND CHIRAL SULFIDE SPACERS

A dicarboxylic acid which served as a mesogen in all poly(ester-imide)s was prepared from 4-aminocinnamic acid and trimellitic anhydride. The acid chloride of this monomer was polycondensed with various chiral diols derived from (S)-3-bromo-2-methyl-1-propanol. Furthermore, copolymers containing various molar ratios of a chiral and a nonchiral spacer were studied. Most chiral poly(esterimide)s form a cholesteric melt and a chiral smectic layer structure in the solid state. The cholesteric melt of three poly(ester-imide)s is capable of forming a Grandjean texture upon shearing. The color of this texture depends on the chemical structure, and it may vary with the temperature (thermochromy). Irradiation with UV light of a wavelength less than or equal to 360 nm allows rapid cross-linking and, thus, fixation of supramolecular order and color.