Mesomorphic phase transitions under UV irradiation for calamitic-discotic bimesomorphic alkoxyazobenzene-triphenylene derivatives

Abstract

A triphenylene derivative which has six 4-tetradecyloxyazobenzene units connected via propylene-ester linkages exhibits both calamitic and discotic LC phases. The SmA-Colr phase transition accompanied by molecular shape change can be reversibly performed by controlling both the temperature and the UV light intensity (λ= 365 nm) under an isothermal condition. The mechanism of the SmA-Colr phase transition under UV-irradiation was studied with GI-SAXS technique to reveal that the amount of cis-isomer of azobenzene unit surely affect the phase transition in the way of destabilizing the mesophases.