Preparation of fluorine-free superhydrophobic and wear-resistant cotton fabric with a UV curing reaction for self-cleaning and oil/water separation

A durable superhydrophobic, self-cleaning cotton fabric prepared with UV curing was prepared by a simple method and used for oil/water separation. Firstly, sulfhydryl silica nanoparticles on the fabric surface were prepared by the Stober reaction (SiO2-SH@cotton). Then, the side chain hydroxyl terminated PDMS was reacted with isocyanate to form an isocyanate terminated prepolymer. The prepolymer terminated by HEMA (vinyl-terminated PDMS (PIH)) was sprayed on the fabric surface, and then the superhydrophobic coating (SiO2-S-PIH@cotton) was formed using UV curing. A series of characterization methods were used to demonstrate the properties of the modified cotton fabric. When the weight gain after PIH spraying was 1.8 wt%, the fabric reaches an optimal state (water contact angle (WCA) of 153 degrees and a sliding angle of 7 degrees). When used in an oil-water separation test, the highest separation efficiency reached 99.1%. In particular, the as-prepared fabric has excellent wear resistance. Compared with that before spraying, the superhydrophobicity of the as-prepared fabric has no obvious decrease after 300 cycles under 200 g of weight or after 100 cycles under 500 g of circular friction. This indicated that surface sprayed polymers have two functions: providing low surface tension and protecting the rough surface formed by silica particles. This process was time-saving, energy-saving, protected the environment, had a low material cost and a strong performance stability. It is hoped that this fabric can be used in the large-scale industrialization of oil-water separation.