Azophenol-Based Liquid−crystalline Elastomers for Light-Driven Actuators

Abstract

Para-substituted azophenols exhibit a fast thermal <i>cis</i>-to-<i>trans</i> isomerization rate in ethanol, which can be transferred to the solid state by obtaining liquid−crystalline elastomeric systems. The absence of protic solvent is compensated by the establishment of hydrogen bonding between azophenol monomers that are close to each other. Opto-mechanical experiments reveal that azophenol-containing liquid single-crystal elastomers are valuable materials for light-controlled actuators exhibiting relaxation times of 1 s at room temperature.