Multifunctional ionogels toughened with spiropyran mechanophores for soft ionotronics

Abstract

Ionogels hold significant potential for a wide range of electrical applications. However, developing mechanically robust, biocompatible, and smart ionogels that are suitable for diverse wearable electronics remains a substantial challenge. Here, we report multi-stimuli-responsive tough ionogels synthesized by incorporating nontoxic ILs into double-network elastomers crosslinked by spiropyran mechanophores. Owing to the structural transformation between the ring-closed spiropyran and the ring-open merocyanine forms of the mechanophores, the designed ionogels exhibit enhanced mechanical properties and responsiveness to light, force, and temperature. Additionally, they possess low toxicity, high ionic conductivity, excellent physicochemical stability, and self-adhesion. To demonstrate the potential of these multifunctional ionogels, we have used them to construct various advanced wearable electronic devices, including strain sensors capable of operating over a wide temperature range, triboelectric nanogenerators for harvesting biomechanical energy, and flexible heaters for cold weather protection. This study could open new avenues for the development of multifunctional soft ionotronics.