PREPARATION OF ORDERED AND CROSS-LINKED FILMS FROM LIQUID-CRYSTALLINE P-VINYLPHENOXY-BASED MONOMERS

The synthesis of the following monofunctional and bifunctional liquid crystalline p-vinylphenoxy-based monomers is described: 4-methoxyphenyl 4-[11-(4-vinylphenoxy)undecyloxy)]benzoate (1), 4-cyanophenyl 4-[11-(4-vinylphenoxy)undecyloxy]benzoat (2) and 3-(4-vinylphenoxy)propyl 4-[4-[11-(4-vinylphenoxy)undecyloxy]benzoyloxy]benzoate (3). Both free radical and cationic polymerization of the monofunctional monomers 1 and 2 yielded side-chain liquid crystalline polymers exhibiting smectic A mesomorphism. The polymers exhibited high molar masses ((M) over bar(n) = 40000 - 100000 g/mol) and relatively narrow molar mass distributions ((M) over bar(w)/(M) over bar(n) between 1.5 and 3). Ordered thin films were prepared by in-situ photopolymerization of monomers 1, 2 and 3 oriented in their nematic mesophases. Thin films of a thermally stabilized ordered side-chain liquid crystalline polymer were prepared by copolymerization of the monofunctional monomer 1 and the bifunctional monomer 3, the latter present in low concentration. The films regained orientation when cooled down from temperatures above the isotropization point (137 degrees C) as evidenced by polarized FT-Raman measurements.