Thermoplastic Polyurethane/Carbon\nNanotube Composites\nfor Stretchable Flexible Pressure Sensors

Abstract

Developing conductive polymer composites\n(CPCs) with high stretchability\nand high resistance response is a challenge in the field of flexible\nsensing. In this study, porous CPCs with a microdome array on the\nsurface are prepared based on thermoplastic polyurethane (TPU) and\ncarbon nanotubes (CNTs). TPU/CNT composites are designed to be strain\nsensors and pressure sensors capable of monitoring external strain\nand pressure stimuli. Due to the excellent electrical properties of\ncarbon nanotubes, the synergistic effect of composite surface microstructure,\nand an internal porous structure, the sensor has greatly improved\nthe detection range and sensitivity of traditional sensors. The sensing\nproperties of CPC materials in terms of strain and pressure monitoring\nare perfectly balanced. The detection ranges of the strain sensor\nand pressure sensor are 0–160% and 0–55 kPa, respectively,\nand the highest sensitivity is gauge factor (GF) = 12.88 (90–160%)\nand sensitivity <i>S</i> = 0.08 (0–6.5 kPa), respectively.\nBased on the reversible change of the CNT conductive network under\ntensile/compression loading, the sensor has excellent stability and\ndurability during cyclic loading. In addition, the TPU/CNT composite\nsensors can monitor human movements, bending of composite components,\nand pressure positions, showing great application prospects in electronic\nskin, wearable smart devices, and human–computer interaction.