Conductive thermoplastic polyurethane composites with tunable piezoresistivity by modulating the filler dimensionality for flexible strain sensors

• DOI: 10.1016/j.compositesa.2017.06.003
• Publication Date: 2017-06-11T01:00:53Z
• Authors: Yanjun Zheng; Yilong Li; Kun Dai; Mengran Liu; Kangkang Zhou; Guoqiang Zheng; Chuntai Liu; Changyu Shen
• Keywords: 02 engineering and technology; 0210 nano-technology

Abstract Conductive elastomer composites based strain sensors have attracted increasing attention recently. In this paper, flexible composites were prepared by incorporating thermoplastic polyurethane (TPU) with zero-dimensional carbon black (CB) and one-dimensional carbon nanotubes (CNTs), respectively. CNTs/TPU showed a lower percolation threshold (0.28 wt.%) and wider sensing range (0-ca.135% strain), compared with CB/TPU (1.00 wt.% and 0-ca. 90% strain). CB/TPU composites exhibited a higher sensitivity with a GF of 10.8 under 20% strain, while CNTs/TPU showed a lower GF of 6.8. In cyclic loading-unloading test, both the two composites showed non-monotonic ‘shoulder peak’ behaviors. For CB/TPU, the ‘first peak’ was higher than the ‘second peak’; interestingly, CNTs/TPU presented a negative strain effect. The discrepancy was mainly ascribed to the difference of filler dimensionality and the evolution of the conductive network.