Fabrication of high-strength superhydrophobic aerogels via air-induced self-crosslinking for efficient oil-water separation

Superhydrophobic aerogels are promising for oil-water separation because of their high porosity and excellent selectivity. However, their complex fabrication processes, hydrophobic instability, and poor mechanical stability have significantly limited their widespread application. In this study, silicone waterproofing agents, cellulose nanofibers, aramid fibers, polyurethane, and silica were incorporated to fabricate high-strength superhydrophobic aerogel (HS-Aerogel) using a freeze-casting method, followed by air-induced self-crosslinking reactions. The hierarchical micro/nano-rough structures, chemical bonding, and integration of multiscale fibers endowed the HS-Aerogel with exceptional superhydrophobicity and mechanical strength. The aerogels demonstrated a contact angle exceeding 150 degrees and a sliding angle of approximately 3 degrees, with a compressive strength reaching up to 0.21 MPa at 30 % strain. Owing to these outstanding properties, the HS-Aerogel exhibited excellent oil-water separation performance, maintaining a stable separation flux exceeding 16,000 L center dot m(-2)center dot h(-1) even after 10 cycles and effectively separating challenging emulsions. This air-induced self-crosslinking reaction took place at room temperature in air, greatly simplifying the traditional fabrication of superhydrophobic aerogels and offering the potential for scalable production. Furthermore, HS-Aerogel also provided feasible solutions for various oil-water separation challenges.