POLYMESOMORPHISM OF OCTAPHENYLCYCLOTETRAS ILOXANE AND ITS POLYMERIC ANALOG POLY[OXY(HEXAPHENYLCYCLOTETRASILOXY-2,6-DIYL)]

Octaphenylcyclotetrasiloxane and its polymeric analog poly [oxy(hexaph enylcyclotetrasiloxy-2,6-diyl)] were studied by differential scanning calorimetry (DSC), X-ray diffraction, and optical microscopy. The mani festations of polymesomorphism in these compounds were established and the type of ordering in mesomorphic modifications was determined. Som e mesomorphic properties of the monomer, which are not related to the geometric shape of the molecule, are inherited by polymer. There is a common factor for monomer and polymer, viz., the high mobility of Ph g roups, which takes place in the same temperature range in both compoun ds, that facilitates their transition to the dynamic high-temperature mesophase. Constrained mobility of side groups leads to the anisotropy of molecular interaction and, hence, to lower lattice symmetry which is observed in the low-temperature mesophase, the dimensionality of th e long-range positional order being retained.