Controlled Actuation of Light-Activated Liquid Crystalline Elastomers Enabled by Tunable Disruption of Order

Light is a compelling stimulus for actuation of materials in applications such as soft robotics as it is contactless, patternable, and programmable. Photomechanical effects in liquid crystal elastomers (LCEs) functionalized with photochromic moieties have been widely studied. Fundamentally, the generation of photomechanical work by LCEs upon exposure to light is governed by disruption of the anisotropic chain configurations of the polymer network.<br/>Photoinduced disruption of order in the LCE can be programmed in numerous ways through careful consideration of LCE network components during fabrication. Here, we show that adjusting the strength of intermolecular interactions amongst mesogens in an azobenzene-functionalized LCE (azo-LCE) enhances the efficiency of light to work conversion. Subsequently, we exploit the relationship between deformation magnitude and crosslinking conditions to find that fabrication method of azo-LCEs offers tunability in photo-induced response. Finally, we extend this understanding to a nontraditional chromophore, enhancing the photomechanical response of diarylethene-functionalized LCE prepared with thiol-anhydride dynamic bonds. In this material, we demonstrate controlled, on-demand, all-optically reversible deformation with reprogrammable actuation modes and shape permanence.