Enhancing the Corrosion Resistance of Epoxy Coatings by Impregnation with a Reduced Graphene Oxide-Hydrophobic Ionic Liquid Composite

Conventional epoxy resin fails as corrosion protection in long-term soaking in water as pores are developing. Here, a modified epoxy coating with enhanced corrosion resistance was fabricated by impregnation with functionalized reduced graphene oxide-hydrophobic ionic liquid (RGO-IL) nano composites. The modified RGO was characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), electrochemical impedance spectroscopy and simulated immersion experiments. Compared to epoxy resin (ER) coatings without RGO-IL nano composites, the ER with RGO nano composites showed higher hydrophobicity in contact angle tests. In electrochemical experiments on Q235 substrates coated with the RGO-IL/ER composite, enhanced barrier properties and excellent corrosion protection was found. A more hydrophobic interface was built, and the nano composite material of RGO-IL was easy to prepare and cost efficient. We speculated that the presence of the ionic liquids also improves the dispersion properties of RGO in ER, and thereby further improving its barrier effect. In addition, the hydrophobic ionic liquid itself had a hindrance to water molecules and chloride ions. The highlight of our work is the combination of the corrosion inhibition of the hydrophobic ionic liquids with the barrier effect of RGO.