LIQUID-CRYSTALLINE BEHAVIOR OF NYLPHENOXY)HEXYL)OXY)(TRIFLUOROETHOXY)PHOSPHAZENE]

The thermotropic liquid crystalline behavior of a mixed-substituent po ly(organophosphazene) containing trifluoroethoxy and (6-(4-phenylpheno xy)hexyl)oxy side chain groups has been investigated by differential s canning calorimetry, polarized optical microscopy, and X-ray diffracti on. Upon cooling from the isotropic Liquid a ''batonnet'' texture meso phase formed, which is indicative of a smectic-like structure as compa red to low molar mass molecules. The texture grows and coalesces to a final texture. The X-ray diffraction pattern of the ''captured'' struc ture upon quench-cooling from the mesophase indicated a mixture of sme ctic C- and A-like phases. The phosphazene backbone layer thickness is approximately 2.4 mo, and the mesogenic (6-(4-phenylphenoxy)hexyl) ox y side chain overlaps in an antiparallel, interdigitated structure wit hin this layered interval. Mesophase formation in the mixed-substituen t polyphosphazene is due largely to the chemical inhomogeneity of the side chain groups, since the single-substituent polyphosphazene contai ning the same biphenyl side chain does not exhibit a liquid crystallin e phase.