Halloysite nanotubes strengthened electrospinning composite nanofiber membrane for on-skin flexible pressure sensor with high sensitivity, good breathability, and round-the-clock antibacterial activity

Abstract

Flexible pressure sensors that can in real-time detect and monitor external stimuli and physiological signals accurately and continuously are highly desirable. However, it is still challenging to prepare stretchable, breathable, and antibacterial substrates that can be served in on-skin flexible pressure sensors. Herein, a stretchable and breathable on-skin flexible pressure sensor with high sensitivity and round-the-clock antibacterial activity is fabricated by integrating silver phosphate nanoparticles modified halloysite nanotubes (Hal@Ag3PO4) into thermoplastic polyurethane (TPU) matrix via electrospinning. The sensor is constructed by using the Hal@Ag3PO4 decorated TPU electrospinning nanofiber membrane as flexible substrates and using silver nanowires/TPU nanofiber composites as dielectric layer. The introduction of Hal@Ag3PO4 nanofillers significantly improves the sensitivity and the mechanical properties of the sensor. In terms of pressure sensing, the device exhibits high sensitivity (6.7 kPa−1), fast response time (60 ms), low detection limit (4.8 Pa), good air permeability (130 mm/s) and well stability of 3000 cycles without fatigue. Importantly, it shows the round-the-clock antibacterial activity for Escherichia coli and Staphylococcus aureus, benefitting for the continuous detection and monitoring by wearing onto human skin. Except that, we build a sensor array that can clearly recognize the pressure location. Thus, this strategy that combines electrospinning TPU nanofiber membranes with Hal@Ag3PO4 antibacterial nanofillers demonstrates a low-cost and scalable manufacturing technology for on-skin flexible pressure sensors with promising applications in electronic skin and smart wound dressing.