Bio‐Inspired Semi‐Active Safeguarding Design with Enhanced Impact Resistance via Shape Memory Effect

Abstract Inspired by creatures reducing impact damage, a novel semi‐active protection strategy to enhance impact resistance through structural adjustment is proposed. The heat‐activated shape memory composites (PCLE) consisting of polycaprolactone (PCL) and shear stiffening elastomer are first prepared. The PCLE with 50 wt.% PCL (PCLE‐50%) presents tensile strength of 0.46 MPa, fracture strain of 148%, high shape fixity and recovery rates (97.9% and 91.1%), and stable shape‐memory repeatability. Furthermore, various PCLE‐50%‐based structures are fabricated, which show reinforced anti‐impact performance after shape‐shifting. Loading from 300 mm, the maximum drop hammer impact force of no protection, PCLE‐50%, and deformed assembled single‐branch structure are 3.98 kN, 1.75 kN, and 0.93 kN, respectively. Additionally, assembled complex structures also exhibit exceptional energy absorption properties. Ultimately, intelligent clothing is successfully manufactured. Besides good anti‐impact effect, the clothing shows excellent thermal insulation capabilities whose surface temperature is 31.7 °C after heating for 600 s at 42 °C. This study provides an innovative means to develop deformable, wearable, and intelligent protective devices.