Polymer brush-grafted ZnO-modified cotton for efficient oil/water separation with abrasion/acid/alkali resistance and temperature “switch” property

A novel super-hydrophobic cotton material was fabricated via the grafting of PGMA polymer brush and the subsequent immobilization of ZnO nanoparticles and octyltriethoxysilane (OTES). The modified cotton showed a high water contact angle (WCA) of above 151° for all the water droplet with the pH ranging from 1 to 14, and was stable (WCA > 150°) in ammonia or acetic anhydride solutions. In addition, the tensile strength of the modified cotton was 2.05 times that of the original one. However, little change in the superhydrophobicity (WCA > 150°) was observed even after rubbing the modified cotton with 50 g weight for a thousand times. Furthermore, the modified cotton showed the interesting temperature “switch” phenomenon, which endowed the change of the wettability with the change of the temperature. The modified cotton material exhibited enhanced oil–water separation performance with good mechanical stability, pH and abrasion resistance, as well as the “switch” property.