Ferroelectric liquid crystalline polyoxetanes bearing chiral dimesogenic pendants

Abstract

Two new polyoxetanes bearing dimesogenic pendants were prepared and their liquid crystalline properties were studied by differential scanning calorimetry (DSC), polarizing microscopy, and X-ray diffractometry. The dimesogens consist of cholesterol and biphenyl moieties connected through polymethylene spacers. Their biphenyl ends were attached to the oxetane monomer through a hexamethylene unit and the dimesogenic monomers were subjected to cationic ring-opening polymerization. The molecular weights of the polymers were very low and the degree of polymerization was only about 6. The two polymers were found to be thermotropic and formed only the chiral smectic C (Sc*) phase and, thus, their ferroelectricity was studied. Their spontaneous polarization values at the Sc* phase were about 20 nC cm⁻² with responsive times of around 0.3 ms at 7 °C below the clearing temperature.