Liquid crystalline polyoxetanes with two mesogens in the side chain separated by a flexible spacer

The synthesis and thermal behaviour of a new geometry of side chain liquid crystalline polymers consisting on two mesogenic units connected by a flexi ble spacer as pendent groups of a polyoxetane chain is reported. Changes in the length and parity of the spacer lead to different mesophase properties . This feature is analysed in comparison to similar effects found in dimers and in semiflexible main chain liquid crystalline polymers with analogous chemical structure, where S-C* and S-CA Symmetries have been obtained. Odd- even effects in transition temperatures and enthalpy changes are observed i n both monomers and polymers. The symmetry of the mesophases is analysed by means of X-ray diffraction. Evidence for coexistence of different molecula r orderings depending on the thermal treatment was found.