Synthesis of superhydrophobic fluoro-containing silica sol coatings for cotton textile by one-step sol–gel process

Superhydrophobic coatings were successfully fabricated on cotton textiles through a simple one-step sol–gel process. A fluorinated copolymer (PHFA-MPS), as a precursor in the sol–gel reaction, was prepared by copolymerization of hexafluorobutyl methacrylate (HFA) and 3-methacryloxypropyltrimethoxysilane (MPS) as monomers. Then, the fluoro-containing silica sols were formed by alkaline hydrolysis of tetraethylorthosilicate (TEOS) and PHFA-MPS solution in an ethanol solution, which was used to impart the cotton textiles with excellent superhydrophobicity via a facile dip-coating method. The effects of ammonium hydroxide solution (NH₄OH) and PHFA-MPS concentration on the structure of the fluoro-containing silica sols, as well as the wetting behavior, surface morphology, and surface composition of the as-prepared cotton textiles were characterized. The results show that the resultant cotton textiles exhibited excellent superhydrophobicity with a WCA of 153.4° and satisfied stability, which offers a simple procedure to generate the superhydrophobicity on cotton textiles for use in a wide range of fields.