Nano coating containing SiO2 nanoparticles with non-stick properties for easy peeling of car paint from mild steel surfaces

Abstract

Non-stick latex coating enhanced with mesoporous silica nanoparticles (SiO2 NPs) showed promising peeling properties. In order to see the effect of SiO2 NPs, coatings with and without SiO2 NPs applied on pieces of a hollow section mild steel beam as substrate. The grain size, crystal phase structure, specific surface area (SSA) and pore size distribution of the SiO2 NPs was determined using transmission electron microscopy (TEM), X-ray diffraction (XRD) pattern and Brunauer-Emmett-Teller (BET) analysis. Field emission scanning electron microscope (FESEM) and energy-dispersive X-ray spectroscopy (EDS) was used to observe the surface morphology and composition of the coated samples. The contact angle was measured for three different liquids on the surface of the samples namely, 1-bromonaphthalene (nonpolar), formamide and distilled water (polar) in order to calculate the surface energies per unit area and hysteresis contact angles. The result showed that adding SiO2 NPs increases the hydrophobicity and decreases the surface energy of the surface. One of the applications of such a coating is to protect the surface from paint sticking to it. For this purpose, the coating with and without SiO2 NPs is applied on a mild steel substrate and then painted by resin-based automotive paint. The pull off test showed that the adhesion is reduced by addition of SiO2 NPs. In addition, to see this application in industry, the coating with SiO2 NPs is applied to a skid and placed in the painting line of an automotive factory for 12 working days. After removing from the line, the coating and the paint on it were easily peeled from the skid either manually with a spatula or by a water jet cleaning machine (100 bar at spraying angle of 45°) compared to a bare skid.