Preparation and characterization of nano-SiO2/fluorinated polyacrylate composite latex via nano-SiO2/acrylate dispersion

The organic nano-SiO2/acrylate dispersion in which methyl methacrylate (MMA) and butyl acrylate (BA) in the micelles act as dispersing media of nano-SiO2 was prepared by sol–gel method with tetraethyl orthosilicate (TEOS) as precursor, hydrochloric acid as catalyst and methacryloylpropyl trimethoxysilane (MPS) as modifier. Subsequently, the nano-SiO2/fluorinated polyacrylate composite latex was synthesized by two-stage semi-continuous starved emulsion polymerization based on the organic nano-SiO2/acrylate dispersion. The SiO2/fluorinated polyacrylate composite latex and the resultant films were characterized by Fourier transform infrared spectroscopy (FTIR), dynamic light scattering (DLS), Zeta potential (ζ), angle-resolved X-ray photoelectron spectroscopy (AR-XPS) and contact angle measurements (CA). The nano-SiO2/fluorinated polyacrylate composite latex possessed very narrow particle size distributions and good latex stability. Fluorinated groups had a strong tendency to migrate to film surface and the surface hydrophobicity of the resultant films was remarkably improved. The mass ratio of methyl methacrylate to butyl acrylate (MMA/BA) has an important influence on the hydrophobicity of the composite films. When the content of dodecafluoroheptyl methacrylate (DFHMA) was 6 wt% and the mass ratio of MMA/BA was 1/3, the water contact angle could reach 121°. The possible mechanism of migration and enrichment of fluorinated groups to the film surface under different MMA/BA mass ratio was proposed.