Synthesis of an ultrathin, self-adhesive, tough, and frigostable BP@PVP/TPU ionogel for strain sensors by electrospinning

Abstract

Intelligent wearable strain sensors are indispensable for monitoring human locomotion and human–machine interactions. Herein, we present a nanocomposite ionogel film (thickness of 0.2 mm) prepared using polyvinylpyrrolidone (PVP), polyurethane (TPU), 1-butyl-3-methylimidazolium hexafluorophosphate, and black phosphorus (BP) in a dimethylformamide solution, referred to as BP@PVP/TPU, using the electrostatic spinning. While the ionogel film exhibited exceptional properties, including excellent self-adhesiveness, high tensile strength (1866 %), and high fracture strength (0.59 MPa), at room temperature, it displayed high tensile strength (940 %) and high fracture strength (3.01 MPa) even when stored at −35 °C for up to 15 days. Subsequently, a self-adhesive strain sensor was fabricated from the BP@PVP/TPU ionogel using copper wire. After 1000 pull-up cycles under 30 % strain, the sensing signal remained essentially unchanged, and the sensor exhibited satisfactory adhesion to different substrates (e.g., an impressive adhesion strength of up to 299 kPa to iron sheets). The excellent performance of the BP@PVP/TPU ionogel enabled the developed sensor to monitor various human body movements in real time. This approach is both economical and convenient and provides an innovative avenue for developing next-generation wearable strain sensors.