Anti-freezing organohydrogel triboelectric nanogenerator toward highly efficient and flexible human-machine interaction at − 30 °C

Human-machine interaction is crucial for mobile communications, Internet of Things , intelligent medical care, and intelligent robots. There is an increasing interest to develop the next generation of flexible human-machine interactive devices based on stretchable ionic conductive polymer gels . However, due to the nature of polymer gels, the devices turn brittle and the ionic conductivity dramatically drops at subzero temperatures, thus restricted their applicable temperature range. Herein, anti-freezing organohydrogels consist of polyacrylamides/nano-clays networks absorbed with ethylene glycol (EG)/water were designed. The anti-freezing binary solution provides excellent properties for organohydrogels at − 30 °C, including tensile modulus of 29.2   kPa, an ultimate tensile strain of 700%, the ionic conductivity of 1.5 × 10 −3   S   m −1 , transparency of 91%, and rapid self-healing. The flexible organohydrogels electrodes were assembled with elastomers to prepare triboelectric nanogenerators (TENGs), which were further attached on fingers to develop human-machine interactive keyboards. The voltage signals produced by the keyboards in contact with many surfaces were collected, coded, and interpreted as letters and punctuations, then displayed on a monitor. We demonstrated typing by using the self-powered flexible keyboard at − 30 °C. This work may benefit the development of anti-freezing soft materials, self-powered sensors, and wearable human-machine interaction communication device systems.