Preparation and application of strain sensing fibers resistant to temperature interference

To meet the application demands of flexible strain sensors in complex environments and address the issues of temperature-induced resistance drift, low signal accuracy, and poor wearing comfort inherent in conventional flexible strain sensors, this study prepared core–shell structured fibers with a near-zero temperature coefficient of resistance (TCR) by combining silver nanowires (AgNWs) with a positive temperature coefficient and multi-walled carbon nanotubes (MWCNTs) with a negative temperature coefficient. Using a coaxial wet-spinning technique, thermoplastic polyurethane (TPU) was employed as the core layer, and AgNWs-MWCNTs/TPU as the shell layer, enabling continuous fabrication of one-dimensional flexible sensing fibers with excellent stretchability. The influence of the mass ratio of AgNWs to MWCNTs on fiber formation and the temperature coefficient of resistance (TCR) of fiber was systematically investigated to obtain strain-sensing fibers with balanced electrical conductivity, mechanical strength, and temperature interference resistance. Results showed that at an AgNWs:MWCNTs mass ratio of 1∶0.64, the TCR was as low as 187 ppm/℃ over a temperature range of 0–70℃, demonstrating outstanding temperature stability. Under varying ambient temperatures, the sensing fiber accurately monitored human finger joint movements. This work provides a novel strategy for the design and development of temperature-resistant flexible strain sensors.