Functionalization of stainless steel 316L with corrosion resistant polymer films

Stainless steel 316L (SS316L) is a commonly employed alloy with high corrosion resistance due to its chromium content. However, in marine environments it is susceptible to pitting corrosion because of the presence of chloride ions, which leads to a breakdown of the passive oxide layer. Here, we present a surface modification which impedes corrosion by employing surface-initiated atom transfer radical polymerization utilizing three common monomers, styrene, methyl acrylate, and methyl methacrylate via an improved surface-initiated polymerization route. The organic films were characterized by infrared spectroscopy, atomic force microscopy and contact angle goniometry. The electrochemical activity of the surface was monitored by cyclic voltammetry and electrochemical impedance spectroscopy. Modifications resulted in up to 99.9% fractional surface coverage and protection efficiencies of up to 99.3% with no decrease in coating coverage in saline conditions over a 72 hour period. Furthermore, SEM analysis of the polymer modified substrates indicated no pitting after simulated corrosion. These electrochemical and imaging results indicate that these new films could be effective in protecting against corrosion.