Fabrication of strain-sensing fibers with silver nanoparticles and reduced graphene oxide via wet spinning.

To advance the industrialization of flexible strain sensors, an innovative flexible sensing fiber was developed through a sophisticated wet spinning process. Silver trifluoroacetate and graphene oxide (GO) were combined with thermoplastic polyurethane (TPU) to prepare the fibers via wet spinning. Ascorbic acid was used toin situreduce the silver trifluoroacetate and graphene oxide within the polyurethane, causing the growth of silver nanoparticles to bond with reduced graphene oxide, forming a dual conductive pathway. This resulted in the creation of silver nanoparticles/reduced graphene oxide/polyurethane fibers (AgNPs-rGO-TPU sensing fibers). The tensile and sensing properties of AgNPs-rGO-TPU sensing fibers under different parameters were investigated. The results showed that with 25 wt% TPU as the matrix, 30 wt% silver trifluoroacetate, and 1 wt% graphene oxide, the fibers achieved an optimal balance of mechanical and sensing properties. The tensile strength was 7.69 MPa, the elongation at break was 370.75%, and the toughness modulus was 18.45 MJ m^-3. The AgNPs-rGO-TPU sensing fibers effectively detect external stimuli, exhibiting high sensitivity over a wide strain range (gauge factor is 4.25 below 5% strain, 24.79 in the 5%-25% strain range, 23.06 in the 25%-80% strain range, and 21.32 in the 80%-110% strain range), with a conductivity of 163.17 ms·cm^-1. They can stably recognize movements and physiological signals from various parts of the human body, showing good application prospects.