Self-Assembly of Impact-Resistant and Shape-Recoverable Structures Inspired by Taiwan Rhinoceros Beetles.

Taiwan rhinoceros beetle (Trypoxylus dichotomus tsunobosonis) forewings, covered with micrometer-scale sandwich structures, can dissipate impact energies to protect the membranous hindwings underneath. Bioinspired by the forewings, monolayer silica colloidal crystals are self-assembled and utilized as structural templates to engineer sandwich structures, which are supported by nonclose-packed shape memory polymer-based structure arrays. These sandwich structures provide sufficient space for the structural supports to be contorted under external stresses, facilitating the dissipating of impact energies. Importantly, the deformed structures, accompanied by diminished impact resistances, can restore their original states through manipulating the corresponding stimuli-responsive structural transitions under ambient conditions. To gain a better comprehension, the dependences of the structure arrangement, structure size, and structure shape of structural supports on the recoverable impact-resistant capabilities are systematically investigated in this research.