Lightweight, elastic and superhydrophobic multifunctional nanofibrous aerogel for self-cleaning, oil/water separation and pressure sensing

Developing a durable, lightweight, and robust aerogel with multifunctional characteristics is greatly desirable but remains challenging these days. Herein, an environment-friendly and original nanofibrous aerogel with integrative performance was constructed through the combination of nanofibrous aerogels’ forming technique and post-treatment modification approach. The obtained aerogel has a hierarchical porous structure consisting of flexible polyacrylonitrile nanofibers (PANF), a functional polyvinyl alcohol (PVA) polymer, conductive carbon nanotubes (CNTs), and hydrophobic octadecylamine functionalized reduced graphene oxide (ODA-rGO), endowing it with ultralow density (20.54 mg cm−3), superior compressibility and recoverability, outstanding fatigue resistance over 1000 cycles. The hydrophobic ODA-rGO coating imparts the hydrophilic PANF/CNT aerogel superhydrophobicity (154°), contributing to a splendid self-cleaning ability. Additionally, the aerogel was capable of realizing excellent oil/water separation performances. Both organic solvents and soybean oil could be adsorbed by the aerogel with high adsorption capacity (36.07 to 65.09 g g−1) and good stable in recycling as a result of its hierarchical porous structure and good hydrophobicity. It was noteworthy that the aerogel composite can be used as a piezoresistive sensor, exhibiting high sensitivity (33 kPa−1 in the range of 0–2 kPa), low detection limit (1% strain), fast response (160 ms), and good durability (over 1000 cycles). Further, it was demonstrated that the composite can be used to monitor various human activities in real time. These advantages make it an excellent candidate for smart garments, high-efficient oil/water separation and human motion detection.