Intelligent Sensing System of the Car Seat With Flexible Piezoresistive Sensor of Double-Layer Conductive Network

A highly sensitive and flexible piezoresistive sensor is fabricated by Spacial Confined Forced Network Assembly (SCFNA) method in this paper. Polydimethylsiloxane (PDMS)/ short carbon fiber (SCF)/ carbon nanotube (CNT) composite with a V-shaped groove microstructure on surface is prepared as the flexible sensitive components. Because the size of SCF is larger than the microstructure mold, SCF is hard to enter the microstructure. So a double-layer conductive network is constructed by spacial confined assembly of microstructure mold, so that pure CNT network is in the layer of microstructure and the SCF/CNT network is in the layer of non-microstructure. As SCF is more effective in enhancing the conductivity of PDMS than CNT due to its larger aspect ratio and more compact network, the conductivity of SCF/CNT network is higher than CNT network. But the stability and sensitivity of CNT network is higher than SCF/CNT network because the smaller size and more homogeneous dispersion of CNT. Therefore the laminating of SCF/CNT network and CNT network with microstructure on surface could have synergistic effect to improve both the conductivity, stability and the sensitivity of sensor. The accuracy rate of the sensing system can reach 91.1%, which provide the relevant basis for the intelligent control of the car seats.