Facile fabrication of highly-stretchable, low-hysteresis and notch-insensitive ionogels for strain sensors

Ionogels hold great promise for the fabrication of advanced flexible electronic devices owing to their outstanding high conductivity, wide operating temperature and electrochemical stability. However, ionogels prepared by traditional strategies commonly suffer from a conflict between toughness and low hysteresis, limiting their application. Here, a facile and efficient strategy is proposed to fabricate highly stretchable, tough and low-hysteresis ionogels that feature inorganic-organic elastic microspheres of SiO2/PnBA serving as a chemical cross-linker. When subjected to stretching, SiO2/PnBA particles enable the transmission of tension through deformation with low energy dissipation, then they rapidly recover their structure after release of the stress. Due to the elaborately designed network structure, highly stretchable and tough ionogels with low hysteresis are achieved. Furthermore, these materials exhibit unique notch insensitivity as the stress concentration at the crack tip can be effectively alleviated. When exploited as a strain sensor, they exhibit superior sensitivity over a wide range of strain (1%-500%). This work proposes a strategy for replacing chemical/physical cross-linking with flexible and deformable micro-domains to fabricate high-performance ionogels with combined high stretchability, toughness, low hysteresis and notch insensitivity.