The molar mass effect on phase transition of a chiral side chain liquid crystal poly 4 acryloxyloxy undecanoloxy 4′ [ s( ) 2 methylbutyloxyloxy] biphenyl (PA 11) was studied in the present work. The experimental results show that the mesomorphic temperature range depended on the degree of polymerization ( DP ) of polymer. The PA 11 with DP below 7 exhibits an enantiotropic S A mesophase
while polymer with DP over 7 displays both S A and S * C enantiotropic mesophases.Moreover
molar mass distribution has an effect on liquid crystalline behaviour of polymer.