Synthesis and Characterization of the β-Diketone Based Side Chain Liquid Crystalline Random Copolyphenylsilsesquioxane and Its Metal Complex

Abstract The attachment of low molecular weight β-diketone compound to random copolyphenylhydrosilsesquioxane (abbr. as Ph-T) backbone gave rise to the formation of β-diketone based side chain liquid crystalline copolyphenylsilsesquioxane (abbr. as Ph-DK). Its copper complexes (abbr. as Ph-DK-Cu) were prepared following a heterogeneous reaction procedure. The structures of the Ph-DK and their copper complexes were well characterized by IR. NMR and GPC. The DSC heating curves of the Ph-DK-Cu show three endothermic transitions. The first transitions are from crystalline state to liquid crystalline state (I), the second transitions are from liquid crystalline state (I) to liquid crystalline state (II), and the third transitions are from liquid crystalline state to the isotropic liquid. The Ph-DK-Cu are thermotropic liquid crystalline polymers. Their clearing temperature and mesophase range ΔT are lower than those of the corresponding Cu-coordinated β-diketone based copolymethylsilsesquioxane liquid crystalline polymers. The influence of the content of the Cu2+ on the Ph-DK-Cu has been discussed. The chemical incorporation of metal ion into polysilsesquioxane molecule can change the liquid crystal molecular arrangement and the transition temperature.