New Thermotropic Polymers with Flexible Backbone and Mesogenic Side Chains: Blends with Small Molecule Liquid Crystals

A new kind of side-chains mesomorphic polymers is described, allowing variation of spacer length and degree of substitution. Differential scanning calorimetry and polarising microscopy allow the measurement of the mesophase spread and observation of characteristic textures. A large biphasic gap is observed between isotropic and anisotropic phases. This phenomenon might be due to differences in the substitution degree and tacticity of the samples. In the case of some small molecules liquid crystal-polymer blends, a segregation of the various components also induces a new phenomenon, i.e., a “pseudo reentrant” smectic phase in the biphase. Other properties of this polymer in cyanobiphenyls solutions are described such as the influence of the degree of substitution, spacer length, and low molar mass liquid crystal tail length, on phase diagrams.