Stress and Magnetic Field Bimode Detection Sensors Based on Flexible CI/CNTs–PDMS Sponges

This work reports porous carbonyl iron particles/multiwalled carbon nanotubes-polydimethylsiloxane composites (PCMCs) with high flexibility and low density. In comparison to the solid product, the porous PCMC possesses a larger elongation and deformation. Because of the excellent magnetic-mechanic-electric coupling performance, the flexible composite exhibits bimode sensitivity to both the external stresses and magnetic field. Typically, the normalized resistance variation (Δ R/ R) of PCMC reaches 82.8% and 52.2% when the compression strain and tension strain are 60% and 50%, respectively. Moreover, the Δ R/ R induced by bending, twisting, and magnetostress also changes remarkably. When a 144 mT magnetic field is applied, the Δ R/ R of PCMC increases with 3.6%. To further understand the magnetic-mechanic-electric coupling mechanism, a conductive network sensing model is proposed and analyzed. Finally, on the basis of the bimode PCMC sensor array, a smart chessboard which can precisely discriminate special chesses with different masses and magnets is developed. This study provides a new fabrication method for next-generation three-dimensional smart sensors toward artificial electronics and soft robotics.