Mesogenic properties and studies of the photoisomerization process in solutions of branched azobenzene derivatives with ester group

Fifteen azobenzene derivatives with ester group were synthesized. All presented materials can be grouped into five various classes with different branching type and length of ester moiety. During this study the liquid-crystalline properties and the kinetics of trans-cis photoisomerization phenomenon were investigated. The obtained results clearly show that introducing of branched chain into chemical structure of molecules significantly decreases the temperatures of phase transitions. Therefore, very simple liquid-crystalline polymorphism (only smectic A) was observed. Moreover, the kinetic constants of isomerization process were calculated. Performed studies allow to determine the correlation between investigated properties and the chemical structure of presented materials. (C) 2016 Elsevier B.V. All rights reserved.