Superhydrophobic Polyvinyl Butyral‐Based Coating on Cotton Fabric for Oil–Water Separation and Photocatalytic Degradation

ABSTRACT With the rapid development of modern industry, oil pollution incidents frequently occur and seriously threaten the ecological environment. Herein, a facile two‐step dip‐coating method was proposed to prepare polyvinyl butyral (PVB)‐based superhydrophobic coating on cotton fabric (CF) for oil–water separation. First, a PVB/titanium dioxide (TiO 2 ) crosslinked composite layer was covered on CF with hexamethylene diisocyanate trimer (HDTI) as crosslinker to construct a micro‐nano structure and generate strong adhesion. Second, octadecanamine was chemically grafted on the PVB/TiO 2 layer through the addition reaction with the excess isocyanate groups of HDTI to provide low surface energy. The obtained CF showed superhydrophobicity with a high water contact angle of 156.0 o and a low water sliding angle of 3.6 o . After tape peeling, ultrasonication, sandpaper abrasion, and water flow impact tests, the CF still maintained its superhydrophobic characteristic, demonstrating good durability. In addition, the CF showed high separation efficiency of 99.16% for cyclohexane‐water mixture and maintained 98.73% after 15 separation cycles. Moreover, due to the incorporation of TiO 2 nanoparticles, the CF could degrade organic dye under UV irradiation. Our findings provided a simple and low‐cost strategy to prepare superhydrophobic coating on fabrics for oil–water separation, showing great application potential in the field of oil‐pollution treatment.