Molecular engineering of liquid-crystalline polymers by living polymerization. Part 16.—Tailor-made Sc* mesophase in copolymers of (S)-(–)-2-methylbutyl 4′-(ω-vinyloxyalkoxy)biphenyl-4-carboxylate with undecanyl and octyl alkyl groups

Abstract

The synthesis and living cationic polymerization of (S)-(–)-2-methylbutyl 4′-(8-vinyloxyoctyloxy)biphenyl-4-carboxylate (14–8) have been described. Poly(1-{8-[4′-(2-methylbutoxycarbonyl)biphenyl-4-yloxy]octyloxy}ethylene)i.e. poly(14–8) with degree of polymerization (DP) 17 exhibited also an enantiotropic un-identified SX mesophase. Copolymers of 14–8 with (S)-(–)-2-methylbutyl 4′-(11-vinyloxyundecanyloxy)biphenyl-4-carboxylate (14–11) were synthesized to cover the entire range of composition at DP = 15. The phase behaviour of these copolymers was investigated and was demonstrated to be similar to an ideal solution derived from the structural units of poly(14–8) and poly(14–11). This copolymerization experiment allowed the synthesis of copolymers exhibiting, depending on composition, an SC* mesophase from below 10 °C up to 50–80 °C.