Thermoplastic and Electrically Conductive Fibers for Highly Stretchable and Sensitive Strain Sensors

Stretchable and conductive fibers have attracted immense interest in the fields of electronic skin, smart textiles, and environmental monitoring due to their inherited unique characteristics. Although various types of stretchable fibers have been investigated, the complicated fabrication and high cost of the specifically designed fibers have greatly hindered the broad applications of the sensors. This work reports the use of thermoplastic polyurethane (TPU) integrated with a semiliquid metal (SLM) to fabricate SLM-TPU fiber (namely, STF) through traditional melt extrusion. The interaction between SLM and TPU enables STF to be highly sensitive (gauge factor (GF): 177-240) and stretchable (strain: 421%) resistive sensor. Besides, this work discovers that TPU could act as an effective adhesive to conveniently construct different structures from the fibers, such as hexagonal-prism, double-helix and mesh textures. These diverse structures enhance the tensile strength and strain of STF. In addition, the phenomenal sensitivity and stretchability make the STF a rapid-response strain sensor with the ability to monitor human motion.