Synthesis of fluorine-containing latexes with core–shell structure by UV-initiated microemulsion polymerization

Abstract

A core–shell structure of fluorine-containing polyacrylate latex was synthesized by UV-initiated two-stage microemulsion polymerization from styrene (St) and hexafluorobutyl acrylate (HFA) in the presence of Irgacure 2959 as hydrophilic photoinitiator at room temperature. The first polymerization stage took 12 min and the second stage took 10 min. The conversions of the first and the second polymerization stages were about 60 and 85 %, respectively. Fourier transform infrared (FTIR) spectra, transmission electron microscopy (TEM), dynamic light scattering (DLS), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS) and contact angle analysis were used to characterize the properties of latexes and their films. The DLS analysis results indicated that the size of the fluorine-containing nanoparticle is about 20 nm. The TEM photos showed that the particles have core–shell structure and some of the cores are located in the center and the others deviate from the center of particles. From the FTIR and XPS results, we can infer that the fluorine monomer could be introduced into the copolymer and the fluorine-containing polyacrylate mainly occupies the shell part. The TGA results indicated that the fluorine-containing polyacrylate copolymers exhibited higher thermal stability than that of the fluorine-free one. The contact angle analysis results showed that fluorine monomers make the film surface more hydrophobic.