Design of photothermal triggered bilayer morphing composites

This study presents finite element method (FEM) modelling of a bilayered shape-morphing composite, triggered by photo-thermal stimulus. The bilayer consists of an upper-layer of reduced graphene oxide (rGO) reinforced chitosan-methacrylamide (rGO-chitosanMA) and a lower-layer of polydimethylsiloxane (PDMS). The FEM model is experimentally validated and exploited in two case studies that predict shape-morphing for various thickness ratios of upper- to lower-layer. Case one is a parametric study of a bilayer with constant thickness, where the upper-layer thickness is varying from 1 to 99% of the total thickness. In case 2 the upper-layer thickness varies from 1 to 20 µm increasing by 1 µm, while the lower ply thickness varies from 50 to 100 µm increasing by 2 µm. The results describe the shape-morphing trend of the bilayered composite when the upper- to lower-layer thickness ratio changes, and demonstrate a method of designing composite bilayers with triggered and predictable morphing response with potential applications in soft robotics and artificial muscles.