Flexible and wearable carbon black/thermoplastic polyurethane foam with a pinnate-veined aligned porous structure for multifunctional piezoresistive sensors

By Yue Zhai, Yunfei Yu, Kangkang Zhou, Z. Yun, Wenju Huang, Hu Liu, Quanjun Xia, K. Dai, G. Zheng, Chuntai Liu and 1 more. 2020

214 citations recorded by the source corpus.

Abstract In this paper, flexible conductive carbon black (CB)/thermoplastic polyurethane (TPU) foam (CTF) with an intriguing pinnate-veined aligned porous structure was fabricated via a unidirectional freeze-drying process. The density, porosity and average pore size of the composite foam are 0.13 g cm−3, 83.7% and 24.9 μm, respectively. CB particles are uniformly dispersed in the skeleton of the as-prepared foam, resulting in a low percolation threshold of 0.48 vol%. The CTF is capable of distinguishing different compressive strain by change of the relative resistance. Its responsive behaviors towards compressive strain present an excellent linear characteristic with a high gauge factor (GF) up to 1.55. In the piezoresistive tests, the CTF shows a fast response/relaxation time (150/150 ms), fascinating recoverability, excellent response stability within a wide workable detection range up to 80% strain (corresponding pressure of 584.4 kPa) and a superior durability (>10000 cycles), which is mainly related to the pinnate-veined aligned porous structure along the orientation direction. The CTF was then assembled as a wearable sensor to monitor various human motions such as arm bending, squatting, tiptoeing, etc., showing good detection performances. The sensor can also deal with water pollution through oil/water separation, suggesting its multifunctionality and promising prospects in complicated situations.

Subfields: Biomedical Engineering, Electrical and Electronic Engineering, Polymers and Plastics

View Paper: https://www.semanticscholar.org/paper/105e36436552892abd364d10b07f583bd6009f19