All‐Optical Control of Shape

Abstract Photoresponsive liquid crystal elastomers (LCEs) are a unique class of anisotropic materials capable of undergoing large‐scale, macroscopic deformations when exposed to light. Here, surface‐aligned, azobenzene‐functionalized LCEs are prepared via a radical‐mediated, thiol‐acrylate chain transfer reaction. A long‐lived, macroscopic shape deformation is realized in an LCE composed with an o‐fluorinated azobenzene (oF‐azo) monomer. Under UV irradiation, the oF‐azo LCE exhibits a persistent shape deformation for >72 h. By contrasting the photomechanical response of the oF‐azo LCE to analogs prepared from classical and m‐fluorinated azobenzene derivatives, the origin of the persistent deformation is clearly attributed to the underlying influence of positional functionalization on the kinetics of cis→trans isomerization. Informed by these studies and enabled by the salient features of light‐induced deformations, oF‐azo LCEs are demonstrated to undergo all‐optical control of shape deformation and shape restoration.