Synthesis of novel polymethacrylates with siloxyl bridging perfluoroalkyl side-chains for hydrophobic application on cotton fabrics

Three novel fluorinated methacrylate monomers with siloxyl bridging perfluoroalkyl groups were synthesized and characterized. Afterwards, the corresponding polymethacrylate latexes, namely monofluoroalkylsiloxyl polymethacrylate (PMFSMA), bisfluoroalkylsiloxyl polymethacrylate (PBFSMA) and trisfluoroalkylsiloxyl polymethacrylate (PTFSMA), were prepared and coated onto cotton fabrics to make them water-repellent. Particle size, particle size distribution, zeta potential and high-resolution transmission electron microscope (TEM) were tested to assess the emulsion stability and particle morphology. Thermal properties of PTFSMA were evaluated by thermal-gravimetric analysis (TGA). Surface properties of the coated cotton fabrics were characterized by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), water contact angle (WCA), adhesive force and X-ray photoelectron spectroscopy (XPS). It was found that the incorporation of more perfluoroalkyl chains and the annealing process could decrease the surface free energy of polymer film to 13.7   mN/m. Furthermore, the EDS spectra of PTFSMA film after annealing showed an enrichment of fluorine in the film-air interface.