UV-isomerisation in nematic elastomers as a route to photo-mechanical transducer

Abstract

The macroscopic shape of liquid crystalline elastomers strongly depends on the order parameter of the mesogenic groups. This order can be manipulated if photoisomerisable groups, e.g. containing N=N bonds, are introduced into the material. We have explored the large photo-mechanical response of such an azobenzene-containing nematic elastomer at different temperatures, using force and optical birefringence measurements, and focusing on fundamental aspects of population dynamics and the related speed and repeatability of the response. The characteristic time of ``on'' and ``off'' regimes strongly depends on temperature, but is generally found to be very long. We were able to verify that the macroscopic relaxation of the elastomer is determined by the nematic order dynamics and not, for instance, by the polymer network relaxation.

Latex (EPJE class) 12 figures

Cited by in corpus (8)

• Photomechanical coupling in photoactive nematic elastomers
• Bleaching and stimulated recovery of dyes and of photo-cantilevers
• The dynamics of non-linear optical absorption
• Modeling and Simulation of Liquid Crystal Elastomers
• Deep optical penetration dynamics in photo-bending
• Modeling the Mechanisms of the Photomechanical Response of a Nematic Liquid Crystal Elastomer
• Slow dynamics in an azopolymer molecular layer studied by x-ray photon correlation spectroscopy
• Photodynamics of stress in clamped nematic elastomers