Molecular Engineering of Liquid-Crystalline Polymers by Living Polymerization.18. SC* Mesophase in Copolymers of (2S, 3S)-(+)-2-Chloro-3-Methylpentyl 4'-(Omega-Vinyloxyalkyloxy) biphenyl-4-carboxylate with Undecanyl and Octyl Alkyl Groups

摘要

The synthesis and living cationic polymerization of (2S, 3S)-(+)-2-chloro-3-methylpentyl 4'-(11-vinyloxyundecanyloxy)biphenyl-4-carboxylate (15-11) and (2S, 3S)-(+)-2-chloro-3-methylpentyl 4'-(8-vinyloxyoctyloxy)biphenyl-4-carboxylate (15-8) are described. Poly(15-11)s and poly(15-8)s with degrees of polymerization (DP) up to 25 and polydispersities lower than 1.15 were synthesized and characterized by differential scanning calorimetry (DSC) and thermal optical polarized microscopy. Over the entire range of molecular weights poly(15-11)s and poly(15-8)s exhibit enantiotropic smectic A (sA) and chiral smectic C (sC) mesophases. In addition, all poly(15-11)s exhibit a crystalline phase. Poly(15-8)s are noncrystallizable. However, poly(15-8)s with degrees of polymerization higher than 12 exhibit an unidentified sX mesophase. Poly(15-11-co-15-8)X/Y (where X/Y represents the molar ratio of monomer 15-11 to monomer 15-8) with DP of about 15 and polydispersities lower than 1.11 were also synthesized and characterized.