Surface modification of active metals through atom transfer radical polymerization grafting of acrylics

The objective of this work is to investigate the fundamentals of surface-initiated atom transfer radical polymerization (s-ATRP) on metal substrates. Acrylic polymers were grafted from active metal surfaces such as cold rolled steel (CRS), stainless steel (SS) and nickel (Ni) through s-ATRP. Severe deactivation was found with copper bromide bipyridine catalyst. Controlled polymerization with relatively low polydispersities, 1.18-1.35, was achieved using iron bromide triphenylphosphine catalyst. Polymer films up to 80 nm in thickness were obtained within 80 min. Grafting densities were estimated to be 0.58 chains/nm2 for CRS-g-PMMA, 0.55 chains/nm2 for Ni-g-PMMA, 0.18 chains/nm2 for SS-g-PMMA, and 0.66 chains/nm2 for SS-g-PDMAEMA. Electrochemical experiments were also carried out to measure the polarization resistance and corrosion potential of CRS-g-PMMA substrates. Metal surfaces with grafted brush polymer coatings showed significant corrosion resistance. This work demonstrated that the surface-initiated ATRP is a versatile means for the surface modification of active metals with well-defined and functionalized polymer brushes.