Synthesis of a dodecylphenylsiloxane oligomer resin/silica nanocomposite and its application to cotton fabrics

A novel dodecylphenylsiloxane oligomer resin/nanocomposite (PHDESR-SiO₂) was prepared by graft copolymerization between dodecyl modified phenylsiloxane resin with pendent epoxy groups (PHDESR) and amino-functionalized silica nanoparticles (BTEPA-SiO₂). PHDESR-SiO₂ was then used to prepare a super hydrophobic surface on cotton fabric by a facile solution-immersion process method. Chemical structures, chemical compositions, wettability, surface morphology, and thermal properties were investigated by Fourier Transform Infrared Spectrum (FT-IR), ¹H-NMR spectrum, X-ray photoelectron spectroscopy (XPS), static contact angle analyzer, scanning electron microscopy (SEM), Particle size distribution (PSD) and thermo-gravimetric analysis (TGA). The results showed that the target product PHDESR-SiO₂ has an anticipative structure with many micro/nanostructure tubercles, a cross-linked network hydrophobic organosilicon resin film and many clusters of cylindrical dodecyl molecular brushes. This created super hydrophobic structure on the surface of the treated cotton fabrics. XPS analysis indicated that the long carbon chain groups had a slight tendency to enrich the film-air interface. In addition, PHDESR-SiO₂ can provide good hydrophobicity for the treated fabric. As the dose of PHDESR-SiO₂ increased, the hydrophobicity of the treated fabric enhanced and consequently the water static contact angle reached 152.5 °. This had little influence on the softness, color, and gas permeability of the fabrics. This makes it slightly stiff at high doses, and the super-hydrophobic cotton fabric also had good launderability.