Superhydrophobic and wearable TPU based nanofiber strain sensor with outstanding sensitivity for high-quality body motion monitoring

Abstract

Nowadays, stretchable, flexible and wearable strain sensors are becoming more and more important for their abilities to monitor human health and body motions. However, it still exists some challenges to develop a new type of strain sensor with high sensitivity, the properties of anti-harsh environments and multidirectional monitoring. Here, we put forward a flexible, multi-functional, wearable and conductive nanofiber composite (WCNC) strain senor with handy preparation method, consisting of elastic thermoplastic polyurethane (TPU) with decorated acid modified carbon nanotubes (ACNTs), coupled silver nanowires (AgNWs) and solidified polydimethylsiloxane (PDMS). The sequential decorations of ACNTs, AgNWs and PDMS enhance the conductivity, superhydrophobicity, and strain sensing performance of the TPU-based nanofibrous membrane. The WCNC (TPU/ACNTs/ AgNWs/ PDMS) possesses a quite low resistance about 1.22 Ω/cm2 (conductivity is up to 3506.8 S/m), superior superhydrophobicity (contact angle is up to 153.04°) and self-cleaning property. Furthermore, the WCNC strain sensor possesses high sensitivity and large working strain (gauge factor is nearly 1.36 × 105 with the working strain ranging from 38% to 100%), which illustrates that the WCNC has a quite large work strain under extremely high GF, and has never been reported before. On account of its outstanding sensing performance, the WCNC can be used to monitor the different movements of human bodies and simultaneously monitor sensor signals in multiple vertical directions, achieving more accurate results.