A new class of glassy liquid crystal elastomers are studied to understand their light-coupled deformation characteristics. In particular, the photomechanics of azobenzene liquid crystal elastomers is modeled using a nonlinear continuum mechanics approach coupled with time-dependent liquid crystal domain structure evolution to understand light polarization effects on deformation. Light propagation and absorption within the elastomer is modeled using Maxwell’s electro-magnetic equations. By consideration of electric energy due to light absorption, light-induced electrical stresses are introduced which provide the driving force for mechanical deformation via coupling with the azobenzene liquid crystals. A liquid crystal director (i.e., orientation of the liquid crystal molecule) is used to describe liquid crystal evolution and elastomer deformation. This aspect of the model is extended to include 3D effects to accommodate trans-cis-trans photoisomerization. This is coupled to plane stress, nonlinear mechanics to demonstrate key field-coupled mechanics relations governing this class of smart materials. The results show that the model successfully predicts large, bi-directional bending of the polymer film by controlling the polarization of light. The results are consistent with recent experimental data given in the literature.

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