The synthesis of imidazolium-type poly(ionic liquid) and self-assembly of self-healable, anti-freezing, and conductive polyionic gels for wireless strain sensing

Recently, wireless flexible strain sensors have attracted increasing attention in the fields of soft robotics, electronic skin, and health monitoring. Wireless signal transmission overcomes the wiring constraints and immobility of traditional sensors, while the widespread application of gel-based sensors is often limited by the inherent shortcomings of different materials, including low mechanical strength, poor conductivity, and inadequate cold resistance. To address this, this work synthesized the imidazole type poly (ionic liquid) (P(VIm-NH 2 [Tf 2 N])), and fabricated the self-healable, anti-freezing and conductive polyionic gels for use in wireless strain sensors. A key highlight is the direct conversion of a mixed solution of P(VIm-NH 2 [Tf 2 N]), poly (vinyl alcohol), and phytic acid into the polyionic gel at room temperature via supramolecular self-assembly driven by hydrogen bonds and electrostatic interactions, without external stimulation. These dynamic and reversible non-covalent bonds constructed a stable network, endowing the gel with a tensile strength of 705 kPa, an elongation at break of 600%, and 85% self-healing efficiency after 24 h at room temperature. The gel also maintained good flexibility and conductivity at −20 °C. Integrated with a Bluetooth module, the gel sensor enabled wireless monitoring of joint movement, handwriting, and speech recognition on mobile terminals. This work not only provides a new material platform for high-performance wireless strain sensors but also demonstrates an efficient, safe, and environmentally friendly supramolecular assembly strategy that is readily extendable to other functional polymer gels.