Modifier-free sol–gel preparation of cotton fiber@SiO2 superhydrophobic fabric for oil/water separation

The oil/water separation material is beneficial to the respective detection of organic and inorganic impurities in samples by retaining the water-soluble impurities in water and the liposoluble impurities in the oil phase. Cotton fiber@SiO2 superhydrophobic fabric was prepared by a facile modifier-free sol–gel method for oil/water separation. By adjusting the hydrolysis and condensation of TEOS, the preparation of superhydrophobic and superhydrophilic fabrics can be achieved. The hydrolysis and condensation of TEOS are simply controlled by changing the content of ammonia water (as a catalyst). When the content of ammonia water is 3–6 %, cotton fiber@SiO2 superhydrophobic fabric was obtained with the water and oil contact angle of ∼ 156° and 0°, respectively. When the content of ammonia water is 7–10 %, cotton fiber@SiO2 superhydrophilic fabric was realized. In addition, the as-prepared cotton fiber@SiO2 superhydrophobic fabric can be used for the separation of oil/water mixtures with a separation efficiency of 98 %. Finally, the mechanism for the modifier-free sol–gel preparation of cotton fiber@SiO2 superhydrophobic and superhydrophilic fabric was discussed.