A highly stretchable and breathable self-powered dual-parameter sensor for decoupled temperature and strain sensing

Flexible multifunctional sensors with self-powered operating modes are in great demand in long-term wearable applications such as health and structural monitoring, biomedical monitoring, Internet of Things (IoT), and artificial intelligence. However, the currently developed self-powered multifunctional sensors still face problems including high manufacturing cost, complex structure, difficult signal decoupling and unstable power supply. Herein, a crosstalk-free self-powered strain and temperature sensing (SPST) sensor was developed by decorating a thermoplastic polyurethane (TPU) fibrous membrane with carbon black particles (CBPs), carbon nanotubes (CNTs) and poly (3,4-ethylenedioxythiophene):poly (styrenesulfonate) (PEDOT:PSS) through a simple soaking method. For this sensor, CBPs/CNTs and PEDOT:PSS were used as strain and temperature sensing elements, respectively. By utilizing the piezoresistive effect from the CBPs/CNT conductive network and thermoelectric effect from the PEDOT:PSS network, the SPST sensor can simultaneously detect and convert strain and tem-perature stimuli into independent resistance and voltage signals, respectively. The sensor can be further driven by the thermovoltage generated under the temperature difference between human skin and the surrounding environment to achieve self-powered temperature and strain sensing. The sensor maintained a broad strain detection range of 0-140%, and exhibited a temperature resolution of 0.116 K with a fast response time of 2.3 s. As a wearable electronic device that can be directly attached to the skin, the SPST sensor enable precise detection of tiny human motions in a self-powered mode. This work may provide a new proposal to produce a self-powered, stretchable and breathable multi-functional sensor, which is suitable for wearable devices in personal electronic fields.