Synthesis of the hydrophilic additive by grafting glycidyloxypropyl trimethoxysilane on hydrophilic nanosilica and its modification by using dimethyl propionic acid for self-cleaning coatings

In this study, hydrophilic additives were synthesised in a two-step reaction; the first step was the grafting of GPTMS on hydrophilic fumed silica. The epoxy ring-opening reaction was done in the second step by treating it with a secondary acid (Dimethyl propionic acid). These additives were added to the water-based acrylic system to check the hydrophilic character. The additive was characterised using Fourier-transform infrared spectroscopy (FTIR), solid-state silica- nuclear magnetic resonance (NMR), X-ray diffraction (XRD), high-resolution transmission electron microscopy (HR-TEM) with selected area electron diffraction (SAED), Thermo Gravimetric Analysis (TGA), Particle Size and Zeta Potential Analysed by Dynamic Light Scattering (DLS). The additive incorporated coating was characterised with scanning electron microscopy (SEM), contact angle, and stain resistance test to evaluate additive dispersion, hydrophilic and self-cleaning property. The 0.5 phr additive incorporated coating shows the superior hydrophilic and self-cleaning property.