Green materials (DL-methionine/abietic acid)-based epoxy acrylate as promising antimicrobial and antibiofilm agents, and corrosion inhibitors for electron beam curable steel coating in different corrosive media

Abstract

In the current article, two natural molecules (DL-methionine (DLM) and abietic acid (AA)) were used as antimicrobial, and antibiofilm agents and novel corrosion inhibitors in solvent-free coating formulations using electron beam irradiation (EB). After then, all of the coating compositions were sonicated and applied as thin coating films on a variety of substrates; these coated films (epoxy acrylate-based formulations) were then polymerized under an electron beam at dose of 10 kGy. The homogeneity and distribution of AA and DLM in the EB-cured coating films were confirmed via FTIR, water contact angle (WCA), and SEM. Open circuit potential and different corrosion tests (degree of rust, blistering, and adhesion failure at the scribe) were studied for all cured coating mild steel in 3.5% and 0.5 M of NaCl and HCl, respectively. The antimicrobial, and antibiofilm activities, and Kinetics of S. aureus growth were evaluated, while the reaction mechanism was investigated through SEM, and protein leakage assay. The results showed that the coating films containing the two natural materials protect mild steel from corrosion, and the optimum concentration of them was 0.8 wt%. It was also found that the corrosion inhibition efficiency of both DLM and AA at 0.8% gave higher values in 0.5 M HCl with 73.70 and 70.03%, respectively, than those immersed in 3.5% NaCl which gave inhibition efficiencies of 55.00 and 50.50%, respectively. Antimicrobial results indicated that, D1.6/A1.6 possesses the most potent activity against S. aureus (11.0, and 13.0 mm), P. aeruginosa, (10.2, and 10.8 mm), P. mirabilis (13.4, and 14.2 mm), and C. albicans (11.0, and 13.0 mm), respectively. The maximum antibiofilm inhibition % of A1.6 and D1.6 sample was recorded for P. aeruginosa (84.43%, and 77.08%) followed by P. mirabilis (78.58%, and 58.74%), S. typhi (77.81%, and 75.52%), and S. aureus (75.30%, and 72.59%), respectively.