Photochemical-initiated hydrophobic surface modification by benzophenone derivatives and its application on oil-water separation

It is still a huge challenge for industry to manufacture convenient and efficient oil-water separation materials. In this study, benzophenone derivatives with hydrophobic perfluorooctyl groups were synthesized as a crosslinking agent, so that the triplet photosensitizer of benzophenone could be inspired by UV light. Thus, hydrophobic groups were covalently grafted onto the surface of commercial filter papers under mild conditions, which had the advantage of easy availability, low cost, good biodegradability and chemical stability. The relevant reaction mechanism was proposed and confirmed. Moreover, these cellulose-based materials exhibit excellent hydrophobicity and lipophilicity in air, which was used for oil-water separation. The results showed that the modified filter paper was able to separate various oil-water mixtures and surfactant-stabilized water-in-oil emulsions that were driven by gravity in the absence of external stimulus. The findings of this study have significant implications to develop cost-effective low surface energy materials and surfaces, which is potentially possible for large-scale industrial applications.