Ultra-thin, transparent, anti-freezing organohydrogel film responded to a wide range of humidity and temperature

Hydrogel flexible sensors have attracted significant attention in wearable devices because of their inherent stretchability and good mechanical properties. However, most hydrogel sensors reported are only limited to detect strain activity based on flexible and stretchable strain sensing, which cannot provide real-time feedback on the humidity and temperature of the skin surface, this limits the scope of the application of hydrogel sensors. In this work, we fabricate an organohydrogel film sensor with a thickness of only 0.1 mm which is sensitive to humidity and temperature. The prepared organohydrogel film sensor has a wide relative humidity (RH) (20%- 90%) and temperature (-30 degrees C-50 degrees C) detection range, which can accurately record and respond to changes in humidity and temperature on the skin surface. Because of high sensitivity to humidity and temperature, the sensor can stably and repeatedly monitor human respiration with a fast response and recovery time of only 0.41 s and 0.3 s. In addition, the organohydrogel film sensor also has high transparency and anti-freezing properties, which can be precisely attached to the accurate area of skin to monitor signals at low temperatures. Therefore, this work is expected to bring new strategies to construct a new generation of electronic skin sensors and wearable devices that detect multiple stimuli.