The synergic effect of microcapsules and titanium nanoparticles on the self-healing and self-lubricating epoxy coatings: A dual smart application

In the present study, the multi-functional smart epoxy coatings were fabricated by incorporating the 15 wt.% microcapsules containing the linseed oil and various percentage of nano-TiO2 (4, 8, 12 and 16 wt.%). The self-healing and self-lubricating abilities of these nanocomposite coatings were investigated by corrosion and wear tests. The obtained results showed that the smart coating containing the 16 wt.% nano-TiO2 had the best function in the corrosion media, due to healing a scratch in form of layer by layer. By using the microscopically analysis, it was found that the linseed oil acted as lubricant agent in the wear test. Adding 4 wt.% nano-TiO2 had the negative effect on the anti-wear properties, due to forming the nanocomposite debris. However, by increasing the percentage of nano-TiO2 up to 12 wt.%, the anti-wear properties had the enhancing trend. Improving the mechanical function of coatings, forming the nano-TiO2/linseed oil self-suspense and trapping the debris by capsule containers were the characterized mechanisms for improving the anti-wear properties. It was also realized that the formation of nano-TiO2/epoxy skin on the surface of microcapsules and agglomeration of nanoparticles had the negative effect on the wear properties of smart coatings.