PRELIMINARY COMMUNICATION - NOVEL FLUOROCARBON SIDE-CHAIN POLYESTERS BASED ON 3,5-DIHYDROXYBENZOIC ACID

Perfluoroalkyl side-chain polyesters with aliphatic hydrocarbon backbone spacers of different chain lengths have been synthesized in high yield directly from the hydrocarbon diacid and perfluoroalkyl 3,5-dihydroxybenzoate. Molecular weights up to 22000 (M) over bar n were obtained. The linear mesogenic perfluoroalkyl segment lengths -(CF2)(n)- were varied, polyesters with n=10 and 7 showing crystalline and liquid crystalline phases, while with n=6 mainly amorphous polyesters were obtained. The mesophases were investigated by polarizing optical microscopy, DSC and X-ray diffraction. They have a grainy optical texture in the POM and give multiple transitions on DSC. In these polymers both the nature of the mesogenic group and the dilution of the mesogenic side-chains along the polymer backbone can be varied.