Green Preparation of Microcellular Poly(Butylene Adipate‐co‐Terephthalate)/Polyether Block Amides@Multi‐Walled Carbon Nanotube Piezoresistive Sensor with Ultrahigh Strain/Stress Sensitivity

Biodegradable foams possess diverse applications in smart wearables, flexible sensors, and human–computer interaction. Current flexible sensors face the problems of inadequate stress/strain sensitivity, high density, and high content of conductive filler. In this study, microcellular poly(butylene adipate‐co‐terephthalate) (PBAT)/polyether block amides (PEBA)@multi‐walled carbon nanotube (MWCNT) sensor exhibiting stress/strain sensitivity, high resilience, and low conductive filler content was prepared via foaming molding integration. In the foaming molding integration process, PBAT/PEBA foaming beads achieve efficient bonding of inter‐beads, where PBAT molecular chains achieve interfacial diffusion and entanglement as well as PEBA improve the stability and mechanical properties of the product. MWCNT is coated on the surface of PBAT/PEBA beads, forming a segregated structure and good conductive network by ball‐milling technique. Consequently, microcellular PBAT/PEBA@MWCNT sensor demonstrates exceptional piezoresistive properties with a strain response gauge factor of 60.0 and a stress response factor of 0.1 kPa⁻¹. The response time and recovery time reach 50 and 100 ms, respectively. Microcellular PBAT/PEBA@MWCNT sensor shows promising potential for detecting various human body parts, including fingers, knees, and arms. This study presents an effective approach for the fabrication and prospective application of highly sensitive microcellular degradable sensors.