Blueprinted Photothermal Shape Morphing of Liquid Crystal Nanocomposites

Liquid crystal elastomers (LCEs) are an attractive platform for dynamic shape morphing due to their ability to undergo large and rapid strains in response to stimuli. While robust methods exist for patterning the director field to achieve desired target shapes, this strategy cannot be generalized to material systems where high-resolution surface alignment is impractical. Instead of programming the local direction of strain, an alternative strategy for prescribed shape morphing is to program the magnitude of strain in a sheet of constant director orientation. To explore this possibility, we have developed an approach to program photothermal deformation of thin, planar nematic, LCE sheets by spatially patterning the location and concentration of gold nanoparticles (AuNPs). We show that upon illumination in-plane gradients in photothermal heat generation produce spatially-nonuniform strain profiles that drive out-of-plane buckling into shapes prescribed by the spatial distribution of photoactive inclusions. In complement to experimental results, heat transfer and FEM models are developed to understand the mechanics of deformation and shape selection. Finally, we explore the utility of this system for triggering more complex light-induced behaviors such as oscillatory motion.