Highly sensitive stretchable fiber-based temperature sensor enhanced by surface-chemically modified silver nanowires

The real-time monitoring of human temperature can facilitate efficient family health supervision, disaster diagnosis, and treatment. To meet these requirements, there is an urgent need to develop fibre-based temperature sensors with high sensitivity, fast response rates, and excellent stability. This study investigated the positive temperature characteristics of a stretchable and strain-insensitive temperature sensor with a chemically modified silver nanowire (AgNW). The regulation of the surface polymer on the AgNWs using a conductive ligand of polyaniline-L-cysteine ethyl ester hydrochloride (PANI-LCO) improved the network conductivity by decreasing the junction resistance. In addition, the pristine flexibility and helicoid structure of a spandex polyurethane (SP) covered yarn substrate proved advantageous for the ultra-stretchability of the temperature sensor. Therefore, the synergistic effect of the PANI-LCO-AgNWs and the substrate endowed the composite fibre-based temperature sensor with a high-temperature coefficient of resistance (TCR) of 47.4%/°C and a high stretchability of up to 120%. Furthermore, this study investigated the actual characteristics of the sensor required for the high-performance monitoring of human temperatures. Moreover, theoretical calculations of the electrical distribution of the PANI-LCO ligands further confirmed the experimental chemical modification. A fibre-based temperature sensor can be integrated and woven or sewn onto a cloth or glove with high adaptability. This work provides an efficient strategy to control the surface chemical structure of metal nanomaterials as well as the design of fibre-based temperature sensors that are promising for wearable healthcare management systems, artificial intelligence, electronic skin, and smart robots.