Preparation and abrasion resistance properties of EP-PDMS-PVDF-SiO₂ superhydrophobic composite coating

Improving the sandpaper abrasion resistance of superhydrophobic coating is of great significance for its application. Therefore, a superhydrophobic coating with exceptional abrasion resistance was prepared by utilizing epoxy resin (EP), polydimethylsiloxane (PDMS) and polyvinylidene fluoride (PVDF) as binders in combination with four types of nano-sized silicon dioxide (SiO₂) particles as primary fillers. Moreover, micron-sized SiO₂ particles are incorporated as auxiliary fillers to enhance the abrasion resistance of the coating. In this work, the sandpper abrasion resistance of the coating is systematically tested and analyzed. The results of the contact angle test demonstrate that the contact angle and rolling angle of water droplets on the coating surface remain within the range of 156°-165° and 2°-4°, respectively. Sandpaper abrasion tests reveal that 2 μm or 5 μm SiO₂ particles can enhance the sandpaper abrasion-resistance cycles of the coating by 2-3 times. Additionally, it is observed that the grit of sandpaper also affects the abrasion resistance of the coating. If the coating loses its superhydrophobic properties due to abrasion with 9 μm or 6.5 μm grit sandpaper, these properties can be restored by the abrasion of 19 μm or 11 μm grit sandpaper. However, if the coating was abraded by 38, 19 or 11 μm grit sandpaper, the superhydrophobic properties cannot be restored with abrasion of any grit sandpaper. The result analysis shows that small grit sandpapers are more likely to damage the hierarchical micro-nano structure on the surface of the coating. However, this structure can be recovered through the abrasion of large grit sandpapers. Meanwhile, the sandpaper with large grit tends to induce the coating to peel off from the substrate surface.