Highly Stretchable, Conductive, Adhesive, and Self-Powered Ionogel Sensor for Human Motion Detection, Signal Transmission, and Traffic Monitoring

Abstract

Distinguished from traditional power sources such as batteries and capacitors, triboelectric nanogenerators have higher freedom of material selection and application flexibility and thus can fulfill the needs of flexible self-supplied electronic devices for advanced e-skin, human–computer interaction, and sensing. Here, a flexible (1100% of elongation at break, 0.2 MPa of breaking strength), highly conductive and adhesive (120 kPa), and environmentally stable ionogel was fabricated by introducing ionic liquids into a physical cross-linking polymer framework. The ionic liquid built a nonaqueous solvent system that made the ionogel environmentally stable. The introduction of amphiphilic ions both improved the mechanical properties of the polymer network and acted as ion channels to enhance the mobility of the ionic liquid and thus the electrical conductivity. Meanwhile, dynamic hydrogen bonding and dipole–dipole interaction made the ionogel have good adhesion properties. The ionogel can be applied as a flexible sensor for strain and pressure monitoring, and more importantly, the assembly of the ionogel with silicone rubber elastomer films into a sandwich-structured triboelectric nanogenerator enabled its application in scenarios such as self-supplied messaging and all-weather traffic monitoring, and it can also provide wired and wireless signal outputs with fast response (∼0.04 s). This work provides a direction for the application of gel-based electronic devices in the fields of intelligent human–computer interaction, information transfer, health monitoring, and traffic detection.