Thermo-mechanical and photo-luminescence properties of micro-actuators made of liquid crystal elastomers with cyano-oligo(p-phenylene vinylene) crosslinking bridges

Abstract

Nematic liquid crystal elastomer (LCE) micropillars with reversible thermomechanical deformations and photo luminescence (PL) intensity variations were successfully fabricated by introducing a cyano-oligo(p-phenylene vinylene) dye as a chemical crosslinker. The PL intensity of the micropillars decreased and increased reversibly during the thermal-deformation process. We studied in detail the possible factors that influence the PL intensity variations of the micropillars, including temperature variation, contraction/extension and phase transition. The dye molecules mainly kept the “monomer” state in the micropillars during the thermo-activated deformation. It was found that the phase transition from nematic to isotropic of the LCEs played the major role in the PL intensity variations. This kind of micropillar may have potential application in fluorescent soft sensors and actuators.