SYNTHESIS AND CHARACTERIZATION OF MESOGENIC PHTHALOCYANINES CONTAINING A SINGLE POLY(OXYETHYLENE) SIDE-CHAIN - AN EXAMPLE OF STERIC DISTURBANCE OF THE HEXAGONAL COLUMNAR MESOPHASE

The synthesis and detailed structural characterization of phthalocyani ne derivatives substituted by six dodecyloxy side chains and a single poly(oxyethylene) moiety are described. All of the materials possess c olumnar mesogenic properties. The phthalocyanines attached to short po ly(oxyethylene)s possess an ordered hexagonal mesophase (D-ho) of stru cture similar to that obtained from octakis(dodecyloxy)phthalocyanine. However, the Pc attached to a long poly(oxyethylene) side chain displ ays a less ordered columnar mesophase, probably columnar nematic (N-c) , due to steric disturbance of the two-dimensional hexagonal lattice b y the polymeric substituent. This material also displays an interestin g phase separation of the poly(oxyethylene) and alkoxy side chains in the solid state.