Fabrication of PTFE + TiO2/Ag coatings on 316L/polydopamine with advanced mechanical, bio-corrosion, and antibacterial properties for stainless steel Catheters.

This study explores the corrosion resistance and antibacterial properties of a PTFE + TiO₂/Ag coating applied to 316 L stainless steel. To enhance adhesion, a polydopamine interlayer was chemically deposited onto the steel surface. The PTFE + TiO₂ coating was subsequently applied through immersion, followed by the deposition of silver nanoparticles using a chemical method. Optimization of the polydopamine interlayer involved varying temperature, time, stirring speed, and drying parameters. The optimal conditions for the polydopamine interlayer were determined to be 60 °C for 1 h, 300 rpm stirring, and 24-h drying in a freeze dryer. Analytical results demonstrated that both the PTFE + TiO₂ and PTFE/PTFE + TiO₂/Ag coatings exhibited exceptional corrosion resistance, with corrosion currents of 3.3 × 10^-5 and 3.2 × 10^-4 μA/cm², respectively. Antibacterial assessments showcased the remarkable ability of the PTFE/PTFE + TiO₂/Ag coating, containing 5% silver content, to effectively inhibit bacterial penetration within a 6.5 mm radius. Furthermore, this coating displayed a water contact angle of 143°, classifying it as a hydrophobic coating. The photocatalytic efficiency (Rs) was determined to be 3.18 × 10^-3 A/W, a performance level comparable to that of a standard UV sensor. These findings underscore the substantial enhancements in corrosion resistance, antibacterial performance, and hydrophobic characteristics achieved with the PTFE + TiO₂/Ag coating, particularly through the novel optimization of the polydopamine interlayer. This coating exhibits great promise for multifunctional protective applications in diverse fields, particularly demonstrating its suitability for implants and bio-coatings.