Synthesis and characterization of a new family of photoactive liquid crystalline polyesters based on α-​methylstilbene

A liquid crystal polyester and two liquid crystal copolyesters containing -methylstilbene moieties and aliphatic or aromatic spacers in the backbone were synthesized in good yields, with the aim of using them for photosensitive microcapsule preparation. The synthesized polymers were fully characterized with respect to thermal stability, type of mesophase, molecular weight and E-Z photoisomerization. Combination of monomers with different structures allowed adjustment of the polymer characteristics such as degree of crystallinity and glass transition temperature, as verified using X-ray diffraction, polarized optical microscopy and differential scanning calorimetry. Quantitative H-1 NMR and UV-visible experiments were performed in order to investigate E-Z photoisomerization after photoirradiation at 364 nm. Finally, a membrane based on one of these polymers was prepared and it was found that its wettability increased on photoirradiation