Liquid Metal-Graphene composite conductive nanofiber flexible pressure sensor for dynamic health monitoring

Abstract

• Innovative combo of electrospinning & electrostatic spraying for liquid metal nanofiber pressure sensors. • Liquid metal-graphene dual network boosts sensitivity & response speed in flexible pressure sensors. • Stable, durable flexible pressure sensor resilient to temp & humidity, ideal for health monitoring. Flexible pressure sensors nanofibers-based have garnered significant attention due to their applications in smart wearable devices, healthcare monitoring, human–computer interaction, and artificial intelligence. However, developing flexible pressure sensors with excellent conductivity and stability for stable monitoring of small pressures remains a considerable challenge. This study presents a highly sensitive and rapid-response flexible pressure sensor using liquid metal-graphene composite conductive nanofibers. The sensor employs electrospinning and electrostatic spraying techniques to prepare a liquid metal-polyimide matrix material, with polyvinyl alcohol modification significantly enhancing its adhesion. Notably, an ultrasonic impregnation method was utilized to uniformly disperse conductive fillers onto the surfaces of the nanofibers and within the three-dimensional skeletal structure, creating a dual-conductive network that enhances the sensor’s conductivity. The sensor exhibits high sensitivity (3.02 kPa −1 ), rapid response/recovery times (80 ms/200 ms), and a broad detection range (0–90 kPa), along with excellent mechanical stability and durability (5000 loading–unloading cycles). These advantages enable the flexible pressure sensor to detect various signals from minor body movements to larger motions, such as throat swallowing and finger bending. This research provides an effective method for continuous health monitoring and the identification of subtle physiological changes, showcasing its tremendous potential in the fields of smart robotics and prosthetics.