Rosin acid and SiO2 modified cotton fabric to prepare fluorine-free durable superhydrophobic coating for oil-water separation

Currently, fluorides and long-chain aliphatic compounds are the most frequent low surface energy chemicals utilized in the preparation of superhydrophobic coatings, but associated environmental risks and instability restrict their potential application in oil-water separation. This research described a superhydrophobic coating based on rosin acid and SiO2 modified cotton fabric to overcome this challenge. By means of spray impregnation and UV-assisted click reaction, sulfhydryl modified rosin acid (RA), Octavinyl-POSS, and SiO2 were grafted onto the surface of cotton fabric to obtain RA-SiO2 superhydrophobic coating with rough surfaces such as lotus leaf and low surface energy. The RA-SiO2 superhydrophobic coating had favorable self-cleaning ability, and also adsorbed various light and heavy oils to achieve efficient separation of oil-water mixtures. The separation efficiency was 96.3% and the permeate flux was 6110.84 (L⋅m−2⋅h−1) after 10 repetitions. The RA-SiO2 superhydrophobic coating was found to be effective in separating oil-in-water and oil-in-water emulsions, and the separation mechanism was elaborated. In addition, it could effectively separate emulsions even after mechanical abrasion and chemical immersion, and had excellent stability. The fluorine-free and environmentally friendly low-cost superhydrophobic coating based on rosin acid is expected to play a significant potential in oil-water separation applications due to its excellent separation performance.