Biodegradable <scp>PBAT</scp>/<scp>SWCNT</scp> Porous Material for Piezoresistive Sensing and Electromagnetic Interference Shielding

ABSTRACT Porous biodegradable polybutylene adipate terephthalate (PBAT)‐based material, used in wearable electronics for sensing human motion, is beneficial for environmental protection. Although PBAT demonstrates good elongation at break and impact performance, specific studies on its processing, modification, and porous structure are needed. Therefore, PBAT/single‐walled carbon nanotube (SWCNT) porous material was prepared via a salt‐templating method. It was found that part of the SWCNT was embedded in the walls of the pores in the PBAT substrate, while another part was exposed on the pore surface. PBAT served as the structural framework, and SWCNT functioned mainly as the active component, especially the SWCNT exposed on the surface. This unique microstructure imparted the porous material with desirable piezoresistive properties and effective electromagnetic interference (EMI) shielding capabilities. When the material was compressed, the exposed SWCNT was forced into closer contact, increasing the number of electrical transport pathways and further enhancing conductivity. The resulting porous sensor exhibited a notable response to strain up to 100% and demonstrated high sensitivity (1.25) while maintaining robust cyclic stability after 1000 cycles. Human pulse and finger flexion were successfully recorded using the fabricated porous sensor. Moreover, the porous material displayed EMI shielding capabilities, primarily through the absorption of electromagnetic (EM) waves, a phenomenon associated with the rough surface of the pores created by the exposed SWCNT. The overall electromagnetic shielding effectiveness was around 60 dB. Given these advantages, the green biodegradable material PBAT shows significant potential for application in piezoresistive sensors and electromagnetic interference shielding with appropriate modification and preparation.