Abstract In the contemporary context, the growing awareness of diverse microbial microorganisms and the imperative to reduce healthcare costs highlight the crucial demand for antimicrobial materials in human society. Silver, renowned as the most extensively utilized and effective antimicrobial agent, possesses the ability to infiltrate bacterial structures, disrupting their biological systems. Among the various methods for employing silver ions, the preference for zeolites, such as natural clinoptilolite with a crystalline aluminosilicate structure—hydrated, finely porous, and highly water-absorbent due to its ion release mechanism, has gained considerable attention. Polyethylene, particularly heavy polyethylene, stands out among corrosion-resistant polymers, providing insulation, quality, and cost-effectiveness, with production occurring in Iran. Due to its non-toxic nature and minimal environmental concerns, it has garnered significant interest. In this study, silver ions were introduced into the porous zeolite network through an ion exchange mechanism. Subsequently, composite polyethylene coatings with varying percentages (0%, 10%, 20%, and 30% by weight) of silver zeolite were applied to 304 stainless steel using the immersion method. The coatings underwent characterization through X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), adhesion testing, contact angle measurement, and surface roughness assessment. The findings revealed that an increase in silver zeolite content within the polyethylene matrix resulted in coatings that were more homogeneous, thicker, and corrosion-resistant, albeit with a decrease in adhesion. Following the application of the coatings, their corrosion behavior in a 5.3% by weight sodium chloride environment was studied at various durations (10, 24, 40, 70, and 100 days) using electrochemical impedance spectroscopy (EIS). According to the EIS results, adding silver zeolite to polyethylene coatings up to 20% by weight reduced corrosion resistance, while adding 30% by weight increased corrosion resistance in the scratch-resistant coatings. Additionally, the corrosion resistance of the coatings was assessed in a moist 5% by weight sodium chloride environment (Salt Spray) over 800 hours. The salt spray test confirmed the commendable corrosion resistance of the coatings, although the P-30ZA sample with scratches exhibited reduced adhesion due to the presence of loose particles beneath the coating. Finally, by exposing the samples to a bacterial environment containing gram-negative (Escherichia coli) and gram-positive (Staphylococcus aureus) bacteria, their antimicrobial properties were eva‎luated for potential antibacterial applications. The results from the halo and colony count tests suggested an improvement in antimicrobial efficacy against Staphylococcus aureus compared to Escherichia coli with an increasing content of silver zeolite. Keywords: coating, composite, polyethylene, zeolite, silver ion, stainless steel, electrochemical impedance, antimicrobial, salt spray

رحمت اله عمادي , عبدالمجيد اسلامي

علي اشرفي , مهدي رفيعائي