MOLECULAR ENGINEERING OF LIQUID-CRYSTALLINE POLYMERS BY LIVING POLYMERIZATION .31. SYNTHESIS AND LIVING CATIONIC POLYMERIZATION OF (2R,3S)-2-FLUORO-3-METHYLPENTYL RO-4'-(OMEGA-VINYLOXYALKOXY)BIPHENYL-4-CARBOXYLATE WITH UNDECANYL AND OCTYL ALKYL-GROUPS

The synthesis and 'living' cationic polymerization of (2R,3S)-2-fluoro -3-methylpentyl 4'-(11-vinyloxyundecanyloxy)biphenyl-4-carboxylate (18 -11) and (2R,3S)-2-fluoro-3-methylpentyl uoro-4'-(8-vinyloxyoctyloxy)b iphenyl-4-carboxylate (18-8) are described. Poly(l8-11)s and poly(18-8 )s with degrees of polymerization (DP) from 4.5 to 16.7 and polydisper sities less than or equal to 1.22 were synthesized and characterized b y differential scanning calorimetry (DSC) and thermal optical polarize d 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 greater than or equal to 8.7 and poly(1 8-8)s with DP greater than or equal to 10.0 exhibit an unidentified S, mesophase. All poly(18-8)s are non-crystallizable, while poly(18-1)s with DP greater than or equal to 7.2 exhibit a crystalline phase. Poly l[(18-11)-co-(18-8)](X:Y) (where X:Y represents the molar ratio of mon omer 18-11 to monomer 18-8) with DP of ca. 12 and polydispersities low er than 1.22 are also synthesized and characterized. Both the S-A and S-c mesophases of these copolymers exhibit continuous dependences ove r the entire range of copolymer composition.