A mild strategy to construct superhydrophobic cotton with dual self-cleaning and oil–water separation abilities based on TiO 2 and POSS via thiol-ene click reaction

In this work, we proposed a mild and fluorine-free strategy for fabricating robust superhydrophobic coatings with TiO2, 3-mercaptopropyltriethoxysilane (MPTS) and polyhedral oligomeric silsesquioxanes using dip-coating and thiol-ene click reaction. The modified cotton exhibited superb superhydrophobicity with a WCA of 157.6°, which showed anti-wetting property in both water and air. Moreover, the durability of the treated cotton against acid and alkaline solutions, different temperatures, abrasion and peeling tests was verified. The highlight is the dual self-cleaning afforded by superhydrophobicity and photocatalytic degradation. The oil red O was adopted as organic pollutant model and could be decomposed completely with the aid of resultant coating after UV irradiation for 3 h. In addition, the modified cotton could be used as filter material and has the potential in the application of oil–water separation. After seven separation cycles, the separation efficiency still maintained 99.0%, while the WCA of cotton kept as high as 154.6°. Therefore, the above-mentioned features demonstrated that this fluorine-free method could reduce the usage of long-chain fluorinated polymers and prepare superhydrophobic cotton which could be applied in self-cleaning as well as oil–water separation fields.