Molecular Engineering of Azobenzene-Functionalized Polyimides To Enhance Both Photomechanical Work and Motion

Photomechanical effects in polymeric materials directly convert input photonic energy into a macroscopic mechanical output. The photoinitiated mechanical output of these materials is typically dominated by classical mechanics, primarily derived from the material stiffness and sample geometry. Accordingly, large magnitude shape change (e.g., motion) is typically traded for large magnitude force generation. Here, we report on the systematic preparation and comparison of photomechanical effects in a set of isomerically varied linear and cross-linked azobenzene-functionalized materials that demonstrate the critical role of segmental mobility (evident in the magnitude of the β-transition) to assimilate the typically exclusive properties of large force generation and large shape change in a single material.