Comprehensive evaluation of the piezoresistive behavior of carbon nanotube-based composite strain sensors

Abstract Theoretical analysis of the piezoresistive behavior of carbon nanotube (CNT)-based composites is of great importance for understanding the electro-mechanical response of CNT-based composite strain sensors. In this paper, a new and comprehensive analytical model is developed to predict the piezoresistive response of conductive CNT-based composite sensors by considering the effects of CNT aspect ratio, interphase, waviness, dispersion, and so on. Stretching-induced changes in electrical resistance are characterized by the variation of CNT content, CNT orientation, and percolated conductive networks. The developed model is used to systematically evaluate the piezoresistive response of CNT-based composite strain sensors. The effects of the above key factors are examined on the piezoresistive response of CNT-based composite strain sensors. The predictions by the present model show good agreement with the existing experimental data and the theoretical predictions from previous studies. The developed model highlights the physical mechanism and takes full consideration of the key parameters, which can help to gain a deeper understanding of the piezoresistive behavior of CNT-based composite sensors compared with existing modellings. Finally, a meaningful recommendation is made to optimize the design of highly sensitive CNT-based composite sensors.