Photoinduced Topographical Feature Development in Blueprinted Azobenzene-Functionalized Liquid Crystalline Elastomers

All-optical deformation and recovery of complex topographical features is demonstrated within elastic sheets composed of main-chain type azobenzene-functionalized liquid crystalline elastomers (azo-LCEs). The azo-LCEs are synthesized via an orthogonal, two-step reaction between commercially available LC monomers and n-butylamine. By employing surface alignment, the local orientation of the nematic director is spatially complex ("blueprinted"). Exposing the blueprinted LCE films to light as an actinic stimulus generates a photomechanical response which yields reversible shape changes between 2D and 3D shapes. The deformation of azo-LCEs strongly depends on the azobenzene concentration as well as the network structure (i.e., crosslink density). Blueprinting complex director profiles within azo-LCEs yield reconfigurable elastic sheets that can be addressed both remotely and selectively which may have benefit in a variety of applications in aerospace, medicine, and optics.