Lightweight and flexible sensors based on environmental‐friendly poly(butylene adipate‐co‐terephthalate) composite foams with porous segregated conductive networks

Abstract Constructing the microcellular structure in the conductive polymer composites (CPCs) is a promising approach to improve the sensitivity and durability of the piezoresistive sensor. Selectively placing the conductive fillers, to form the segregated network between the polymer region, can effectively improve the electric performance of CPCs. However, few researches have focused on the influence of the polymer bead size on the segregated network and the large‐scale production of spherical polymer beads with low cost is still difficult to realize. Herein, plenty of regular‐shaped poly(butylene adipate‐co‐terephthalate) (PBAT) beads were manufactured through underwater pelletizing process, which was further coated with carbon nanotube (CNT) particles with the assistance of ball milling technology, and eventually the sensor was successfully fabricated through supercritical carbon dioxide (scCO 2 ) bead foaming technology. The lightweight and flexible sensor exhibited the uniform cell structure with the mean cell size of 51.0 μm and cell density of 3.9 × 10 8 cells/cm 3 when the pelletizing cutter speed was 2500 rpm and the foaming temperature was 117.5°C. And the conductivity of the sensor reached 6.5 S/m incorporated with 3 wt% CNT, which possessed high sensitivity, good stability and long‐term durability, attributed to its excellent microcellular structure and segregated conductive network.