A robust and durable superhydrophobic cotton fabric with excellent self-cleaning performance for oil/water separation

Superhydrophobic cotton fabric is regarded as an accessible and efficient technology for oily wastewater cleanup because of high porosity, switch wettability, and low cost. However, the existing superhydrophobic fabrics cannot maintain durable superhydrophobicity during practical application due to poor action force between hydrophobic substance and fabric. Herein, a robust and durable fluorine-free superhydrophobic cotton fabric was successfully fabricated through a facile two-step modification process. Firstly, amino-functionalized SiO2 nanoparticles were chemically bonded to the cotton fabric surface, creating a rough structure with peaks and valleys. Subsequently, the surface was coated with a layer of hydrophobic polydimethylsiloxane (PDMS) for surface modification, resulting in a superhydrophobic surface effective for the separation of oil-water mixtures. The as-prepared superhydrophobic cotton fabric (PDMS-SiO2@cot) presented superhydrophobic property with water contact angle reached 156.7 degrees. Meanwhile, the prepared PDMS-SiO2@cot can effectively separate various oil-water mixtures with high separation efficiency (98.2-99.4%). Furthermore, the superhydrophobic cotton fabric demonstrated remarkable robustness by maintaining its hydrophobic characteristics after being subjected to a series of durability tests, including immersing into various solutions (acidic solution, alkaline solution, and organic solvents), and exposing to ultrasonication and mechanical stress (scraping, adhesive tape peeling, and sandpaper abrasion). In conclusion, the as-prepared superhydrophobic cotton fabric PDMS-SiO2@cot with excellent mechanical stability, chemical resistance, and self-cleaning properties shows considerable potential for oily water remediation.