Molecular engineering of liquid-crystalline polymers by ‘living’ polymerization. Part 31.—Synthesis and ‘living’ cationic polymerization of (2R, 3S)-2-fluoro-3-methylpentyl 3-fluoro-4′-(ω-vinyloxyalkoxy)biphenyl-4-carboxylate with undecanyl and octyl alkyl groups

Abstract

The synthesis and ‘living’ cationic polymerization of (2R, 3S)-2-fluoro-3-methylpentyl 3-fluoro-4′-(11-vinyloxyundecanyloxy)biphenyl-4-carboxylate (18–11) and (2R, 3S)-2-fluoro-3-methylpentyl 3-fluoro-4′-(8-vinyloxyoctyloxy)biphenyl-4-carboxylate (18–8) are described. Poly(18–11)s and poly(18–8)s with degrees of polymerization (DP) from 4.5 to 16.7 and polydispersities ⩽ 1.22 were synthesized and characterized by differential scanning calorimetry (DSC) and thermal optical polarized microscopy. Over the entire range of molecular weights formed, poly(18–11)s and poly(18–8)s exhibit enantiotropic S_A and S_C* phases. In addition, poly(18–11)s with DP 8.7 and poly(18–8)s with DP 10.0 exhibit an unidentified S_X mesophase. All poly(18–8)s are non-crystallizable, while poly(18–11)s with DP 7.2 exhibit a crystalline phase. Poly[(18–11)-co-(18–8)](X : Y)(where X : Y represents the molar ratio of monomer 18–11 to monomer 18–8) with DP of ca. 12 and polydispersities lower than 1.22 are also synthesized and characterized. Both the S_A and S_C* mesophases of these copolymers exhibit continuous dependences over the entire range of copolymer composition.