Liquid crystalline behavior of poly(m-phenylenebutadiynylene)s having a mesogenic substituent

Poly(m-phenylenebutadiynylene)s having a side chain with p-(4-pentylcyclohe xyl)phenyl and cyanobiphenylyl mesogenic core were synthesized from corresp onding m-diethynylbenzene by oxidative polycondensation with a Cu-amine cat alyst under O-2. These polymers showed an enantiotropic nematic phase that was confirmed by polarizing optical microscopy and XRD. Uniaxial alignment of these polymers was carried out by a rubbing technique. Polarizing IR res ults of the aligned samples suggested that the main chain and the mesogenic side chain were aligned in parallel to the rubbing direction.