A flexible, highly sensitive porous EVA pressure sensor based on the supercritical CO₂ foaming, with fire safety

This study employed carbon nanotubes (CNTs) as both the conductive medium and electromagnetic wave absorber, while utilizing black phosphorus (BP) as a flame retardant and interfacial sensitizer. By integrating microwave-induced heating with supercritical CO₂ foaming techniques, a highly sensitive EVA-based flexible foam pressure sensor was successfully developed. Experimental results demonstrated that the fabricated EVA/BP-CNTs (EBC) composite foam exhibited a high sensitivity of 3.93 MPa⁻¹ within the 0-0.3 MPa compressive stress range, along with excellent compressive strength (6.1 MPa), outstanding cyclic stability (over 5,000 cycles), and long-term durability (exceeding 50,000 seconds). Cone calorimetry analysis revealed significant reductions in fire hazards: peak heat release rate (pHRR), total heat release (THR), and peak CO₂ production (pCO₂) were decreased by 34.6% , 18.7%, and 40.9%, respectively, indicating enhanced fire safety performance. Owing to these superior characteristics, the developed flexible pressure sensor demonstrates considerable potential for applications in human motion monitoring, smart electronics, and wearable devices.