Facile fabrication of robust superhydrophobic polyurethane sponge modified with polydopamine- silica nanoparticle for effective oil/ water separation

Porous superhydrophobic materials with high mechanical stability have a significant amount of potential for oilwater separation in practice. In this study, a superhydrophobic material with strong hydrophobic coating adhesion was developed using a polyurethane sponge. The interior and exterior surfaces of the porous polyurethane material were coated using a two-step technique. The sponge was treated with poly (dopamine) to modify its skeleton, allowing the second layer to adhere readily. The second layer of silica applied to the surface of the sponge functions as a superhydrophobic layer. The modified sponge's water contact angle was approximately 156.2 degrees & PLUSMN; 5 degrees, compared to 78 degrees & PLUSMN;2 degrees for the original sponge, demonstrating its superhydrophobic nature. The fabricated sponge is capable of separating and absorbing 43.3-51 times of its initial mass from an oil-water mixture, depending on the type of oil used in the test. Fifteen cycles of oil-water separation were followed by chemical cleaning of the hydrophobic sponge. After undergoing these cycles, the hydrophobic nature and absorption capacity of the produced sponge were preserved. Over a broad pH range, the hydrophobicity of the superhydrophobic sponge was studied, and the results indicated that hydrophobicity was substantially maintained even under harsh pH operating conditions. The water contact angle of the sponge was measured to be 145 degrees & PLUSMN; 1 degrees and 140 degrees & PLUSMN; 1 degrees, respectively, after 12 h of immersion in strong acids and bases.

Automated summary

Porous superhydrophobic materials with high mechanical stability, developed using a polyurethane sponge coated with poly (dopamine) and silica, demonstrate strong hydrophobic coating adhesion and excellent oil-water separation performance. The modified sponge shows a water contact angle of approximately 156.2 degrees & PLUSMN; 5 degrees, and can absorb up to 43.3-51 times of its initial mass from an oil-water mixture. The hydrophobicity and absorption capacity of the modified sponge are preserved even after undergoing multiple cycles of oil-water separation and chemical cleaning.