Synthesis, thermal and optical properties of liquid crystalline terpolymers containing azobenzene and dye moieties

The synthesis, thermal properties and photochemical and photophysical studies of new azopolymers are described. These polymers contain three different types of monomer, each of which is mainly responsible for a particular function: A mesogenic benzanilide, a photochromic azobenzene and a dye unit (a benzoxazole, an anthracene or a stilbene derivative). This approach provides liquid crystalline terpolymers with different spectral properties and with the potential ability to be photoaligned by irradiation and thermotropic self-organization. The polymers have been prepared by random radical polymerisation of the corresponding methacrylate-fucntionalised units. All of the materials show good thermal stability and liquid crystalline behaviour, displaying smectic A or nematic mesophases. Optical properties of the polymers in solution display additive bands in the absorbance spectrum and luminescent properties in the emission region of the individual dye monomers. However, films of these polymers are not luminescent. A study of the absorption and redox properties of the dyes has been performed in order to evaluate the quenching process in the polymers.