Preparation of self-healing water-based epoxy coatings containing microcapsules, treated CeO 2 particles and 8HQS corrosion inhibitor, and study of their anti-corrosion properties

In this research, water-based epoxy coatings were developed to incorporate self-healing and corrosion protection capabilities. To this end, active epoxy-acrylate resin (EA) and benzoyl peroxide (BPO) initiator were separately encapsulated using a two-step water-in-oil emulsion via complex coacervation technique using gelatin-gum Arabic (Ge-GA) shell, followed by in-situ polymerization process using polyurea formaldehyde (PUF) shell. Silane-treated CeO 2 nanoparticles (T-CeO 2 ) were embedded in the core components of the synthesized microcapsules. Subsequently, the microcapsules prepared under different agitation rates and optimized core-to-shell ratios, were characterized using Fourier Transform Infrared Spectroscopy (FTIR) and Thermogravimetric Analysis (TGA). Water-based epoxy coatings were subsequently formulated, incorporating a corrosion inhibitor, 8HQS, and various levels of microcapsules functioning as "smart self-healing additives. " The self-healing and anti-corrosion properties of the coating samples were studied using scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS), and salt spray testing. Following 8 weeks of immersion in a 3.5 wt% NaCl solution, EIS test verified that the E-5MC-8H-Ce sample exhibited the highest corrosion resistance (R p = 0.212 G Omega.cm 2 ).