Bioinspired, Ultra-Sensitive Flexible Strain Sensor Based on Ceramic Fiber Paper With Superhydrophobic and High-Temperature-Resistant Properties

Flexible strain sensors are indispensable components providing repeatable electronic signals responding to mechanical deformations. Nevertheless, there is a stringent demand for flexible sensors to maintain normal performance in daily use and even in harsh conditions, such as high humidity and high temperature. Herein, inspired by scorpions, a highly sensitive flexible strain sensor based on ceramic fiber paper (CFP) with superhydrophobic and high-temperature-resistant properties is developed by a combination of mechanical cutting and spray coating method, which minimizes performance degradation commonly seen in polymer-based and textile-based sensors under harsh conditions. The prepared strain sensor exhibits high sensitivity (gauge factor ≈1254), low detection limit (0.078%), fast response time (108 ms), and notable stability (over 10 000 cycles). The ultra-high sensitivity originates from the existence of the micro-scale cracks. To further improve stability of the device in some harsh conditions, superhydrophobic and heat-resisting coatings consisting of SiO 2 aerogels and SiO 2 nanoparticles are introduced onto the surface of CFP. Owing to the synergistic effect of the high-temperature resistance of ceramics fibers and the coatings, the device operates normally at temperature up to 220 °C with a water contact angle of 159°, showing great promises for harsh conditions, especially in the industrial and aerospace fields.