Modification of stainless steel surfaces for advanced functionalities
Choi, Won Tae
MetadataShow full item record
Due to beneficial combination of corrosion resistance and mechanical strength, stainless steels are widely used in many industries ranging from marine to biomedical. Therefore, the extensive and varied applicability of stainless steels often require exposure to complex and harsh environment including water, oil, seawater, and physiological solution. We focused on modifying stainless steel surfaces to obtain advanced functionalities including hydrophobicity, corrosion resistance, and anti-bacterial properties. Stainless steel 316L (SS316L) is one of the most widely using stainless steels, and thereby modification of SS316L surface is of great practical relevance. Electrochemical etching was employed to modify SS316L surface, and a correlation between the applied anodic potential and SS316L surface topography was founded, which was served as a basis to develop advanced functionalities. A two-step electrochemical etching was performed to develop micro and nanoscale hierarchical structure on SS316L surface, and subsequent deposition of a fluoropolymer led to a super-hydrophobic SS316L surface. Improving corrosion resistance of stainless steels in seawater is significant to ensure the reliability of their maritime applications. Electrochemically modified SS316L surface displayed improved corrosion resistance in 0.6 M sodium chloride solution compared to as-received SS316L. Pathogenic bacterial adhesion on surface is problematic in many stainless steel biomedical applications. Nano-textured SS316L surface was achieved by the electrochemical etching, and the modified SS316L surface displayed reduction in bacterial adhesion on the surface. Furthermore, surface modification was performed on another metallic surface. A simple method to attain a wettability patterned copper surface was devised, and droplet manipulations on the surfaces were demonstrated.