Biomimetic, Programmable, and Part-by-Part Maneuverable Single-Body Shape-Morphing Film

Abstract

Recently, shape-morphing films (SMFs) have been actively researched due to their diverse applications such as soft robotics, soft grippers, and healthcare/wearable devices. Their complex movements are typically made by assembling multiple actuation elements in a single system. However, the unreliability during the assembly process is a critical issue, which has restricted their practical usage. In order to resolve this problem, herein, a biomimetic, programmable, and part-by-part maneuverable single-body SMF is proposed. Programming of the SMF adopts a similar mechanism to Bauhinia variegates, whereby nonequivalent volume changes due to external stimuli cause the bending of the overall film. The patterned elastic modulus of the SU-8 microwall prescribes the preferred bending direction. Part-by-part maneuvering is accomplished by controlling the voltage distribution of the underlying electrothermal heater. The fabricated single-body SMF demonstrates the complex movements of the inchworm (pose stabilization: front-to-back flip and back-to-front flip; basic movements: crawl, left turn, and right turn) and Drosera Capensis (insect gripping via hierarchical morphology). The proposed method for the fabrication of a biomimetic, programmable, and part-by-part maneuverable single-body SMF can successfully replace the conventional assembly process and achieve advanced SMF technology by enabling various complex movements toward practical applications.