Synthesis and characterization of new chiral side chain liquid crystallinepolyoxetanes

Two series of the side chain liquid crystalline polyoxetanes were synthesiz ed via cationic ring-opening polymerization of oxetane monomers bearing pen dant mesogenic units including two chiral carbons. The first two polymers h ave only one pendant group in the repeating unit, whereas the second polyme rs have two mesogenic groups per repeating unit. The oxetane monomer bearin g one mesogenic unit produced high molecular weight polymers, whereas the o nes bearing two mesogenic units at the same carbon in the ring produced onl y oligomeric products. Thermal and liquid crystalline properties of the pol ymers were investigated by optical polarizing microscopy, differential scan ning calorimetry (DSC), and small- and wide-angle X-ray diffractometry. All of the polymers, with the exception of only one polymer, formed liquid cry stalline phases such as S-A, S-C*, and S-I* phases in melts. The molecular arrangement in the smectic phases was interpreted as an intercalated bilaye r structure. An attempt to study the ferroelectric properties of the polyme rs was made, but the results obtained were not satisfactory.