Liquid Crystalline Polyurethane Elastomers Containing Mesogenic Azobenzene Pendant Groups for Photomechanical Actuators

摘要

A liquid crystalline polyurethane elastomer (LCPUE) film has been successfully fabricated by thermal polycondensation of azobenzene mesogenic monomer containing bishydroxyl groups with tolylene 2,4-diisocyanate, linear poly(ethylene glycol) and star pentaerythritol ethoxylate as a cross-linker. The thermotropic film of LCPUE was found to show reversible photoisomerism behavior and could be bent towards the direction of UV-light irradiation. The mechanical force generated in the LCPUE film upon photoirradiation was calculated to be 260-285 kPa according to the dynamic mechanical analysis. Thus this material may promise potential applications in remote light-controlled actuators.