Photochemical Mechanism and Photothermal Considerations in the Mechanical Response of Monodomain, Azobenzene-Functionalized Liquid Crystal Polymer Networks

The potential for wireless transduction of input light energy into mechanical outputs has led to a reinvigorated pursuit of photomechanical effects in polymeric materials and composites. We report here on factors influencing the photochemical mechanism (and thus the mechanical output) in monodomain azobenzene-functionalized liquid crystal polymer networks. Through systematic examination of a representative material with both mechanics and spectroscopic characterization the prevalence of the trans-cis and trans-cis-trans mechanisms is elucidated. Furthermore, the role of light intensity in generating heat (photothermal effects) is also reported.