Ultralight polypyrrole crosslinked nanofiber aerogel for highly sensitive piezoresistive sensor

Nanofiber aerogel is an ideal carrier for constructing high-sensitivity flexible piezoresistive sensors due to its abundant pore structure and excellent mechanical property. However, the reported nanofiber-based piezoresistive sensors generally need tedious high-temperature carbonization process to fabricate the 3D conductive network. Here, a simple, low-cost, and effective method is developed for constructing high-sensitivity all nanofiber-based piezoresistive sensor. The conductive nanofiber aerogel is prepared through freeze-drying method by using in-situ polymerized conductive polymer polypyrrole and electrospinning cellulose acetate nanofiber. Benefiting from the nanofiber skeleton and multistage pore structure, the obtained aerogel possesses an ultra-low volume density of 14.67 mg cm−3. Specifically, the unique nanofiber-based conductive pathways endow the aerogel with an ultra-high sensitivity up to 60.28 kPa−1 in a wide pressure range of 0 ~ 24 kPa. Meanwhile, the flexible nanofiber-based piezoresistive sensor also exhibit excellent cycling stability, which can withstand more than 13,000 cycles of compression. Furthermore, it shows great application potential as a flexible wearable sensor in human motion and health monitoring.