Polyethylene-silver-zeolite composite coatings on stainless steel; corrosion resistance and antimicrobial characteristics

Due to various microbial species and decreasing healthcare costs, antimicrobial materials have become indispensable for human society. Silver ions are among the most widely used and effective antimicrobial agents, capable of penetrating bacterial structures and disrupting their biological systems. In this research, silver ions were first introduced to the porous zeolite network through an ion exchange mechanism. Then, high-density polyethylene (HDPE) coatings containing 0, 10, 20, and 30 wt.% silver zeolite were used to coat AISI 304 stainless steel using immersion methods. Subsequently, X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), adhesion tests, contact angle measurements, and roughness analysis were employed for the characterization of the coatings. The results indicated that increasing the silver zeolite content in the polyethylene matrix resulted in a more uniform coating with increased thickness and corrosion resistance while decreasing its adhesive strength. Furthermore, the corrosion resistance of the coatings using a 5 % sodium chloride salt spray for 800 h confirmed their good corrosion resistance. Finally. The antimicrobial performance of the samples was evaluated against Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Aspergillus flavus using MIC, MBC, MFC, zone of inhibition, and colony count assays. Results demonstrated that increasing silver zeolite content significantly enhanced antimicrobial efficacy, with the strongest activity observed against Staphylococcus aureus. These findings highlight the broad-spectrum antimicrobial potential of silver-zeolite composite coatings.