Abstract
The proposed work is focused on the multi-level corrosion inhibition performance of the double-layered polymeric nanocomposite coatings (DLNCs). For this purpose, Melamine urea-formaldehyde microcapsules encapsulated with linseed oil were synthesized by in situ polymerization technique. A vacuum cycling method was used to load the benzotriazole (BTA) into halloysite nanotubes (HNTs). Furthermore, 3wt.% of loaded HNTs was mixed with epoxy and applied on the clean steel substrate with 150 µm thickness to form the pre-layer. A top layer of epoxy reinforced with 5wt% of MUFMCs was coated on the cured primer layer of BTA loaded HNTs/epoxy with the same thickness and cured for 24 hours resulting in the development of DLNCs. For comparison, single layer epoxy coatings modified with HNTs loaded with BTA and plain epoxy coatings (without any reinforcement) having ⁓300 µm thickness were also developed. Later, the structural, morphological, thermal, and electrochemical analyses of the developed DLNCs were studied. Electrochemical Impedance Spectroscopy (EIS) tests in 3.5 wt.% NaCl solution at room temperature which confirms that DLNCs exhibit superior corrosion resistant properties as compared to single-layer coatings. This improvement can be ascribed to the efficient triggering of the individual carriers in the isolated matrix which in turn increases the overall corrosion efficiency. The promising corrosion inhibition performance of DLNCs makes them attractive for many industrial applications.