Multifunctional Janus-type self-healing MXene/polyionic liquid flexible sensor

Abstract

Integration of electronic sensors with signal processing systems is important for artificial intelligence and intelligent robots. It requires mechanically robust, highly sensitive, and self-healing sensing materials that produce recognizable electrical changes in response to external stimuli. Here, we report a multifunctional Janus-type self-healing MXene/polyionic liquid-based flexible membrane for smart sensing. Flexible MXene-NH2@PIL material with self-healing capacity and high tensile properties was constructed by compounding functionalized MXene with polyionic liquid (PIL) with self-healing ability. Deposition of MXene-NH2 resulted in MXene-NH2@PIL with a unique Janus structure that exhibits a variation in the degree of hydrophilicity on both sides and a certain pH response. The material, which can be warmed to over 70 °C in 8 s, also has excellent photothermal conversion. The internal ionic and hydrogen bonding interactions ensure that it can repair damage at 60 °C. The flexible MXene-NH2@PIL sensor prepared from this material can produce significant signal changes in response to small deformations, such as knocks. The flexible MXene-NH2@PIL sensor can also be worn on the finger to detect the bending motion of the finger. This provides an idea for the preparation of self-healing flexible wearable sensors. This study explores the preparation of flexible self-healing sensors by combining the electron-conducting MXene material and ion-conducting PIL.