Integrated wearable anti-wetting strain sensor with the ability of achieving human joints bending recognition and electricity generation simultaneously

Wearable strain sensor has attracted much attention in human health monitoring, medical rehabilitation, and human-computer interaction. However, it is still a huge challenge for strain sensors to achieve long-term and stable operation in harsh conditions such as exposing to wet environments, directly contacting aqueous solutions or power shortage. Herein, we integrated a wearable, anti-wetting, and self-powered combined-type (WASC) strain sensor consists of three parts: a superhydrophobic and conductive Ti3C2TX (MXene) based composite coating, Ecoflex substrate and a triboelectric nanogenerator (TENG) composed of polyamide and polydimethylsiloxane films. The hierarchical micro/nano mastoid wrinkle structure of the MXene composite coating endowed WASC strain sensor with a wide sensing range (strain over 150%), superior sensitivity (gauge factor of 5678.2), and a stable superhydrophobic surface. Most importantly, the WASC sensor could efficiently monitor real-time human joints bending movements (such as finger bending) and generate electricity simultaneously, without being affected by water, acid, alkali, and salt solution. This described integration strategy of combined-type strain sensor provided a promising method for wearable strain sensors to deal with emergencies such as power shortage, wet environment, or corrosive conditions.