Surface rich in covalently-bonded amine groups have wide end use applications in biomaterials. This article describes functionalization of stainless steel (SS) surface with reactive chemical groups using RF-cold-plasma polymerization of ethylene diamine (ED), acrylonitrile (AN), and acetonitrile (AcN). The effect of RF plasma power and frequency (40 kHz and 13.56 MHz) on surface chemistry was investigated by electron spectroscopy for chemical analysis (ESCA) and FTIR. It was demonstrated that all the plasma-deposited films consist of secondary and tertiary amines, imines, and amides with a small concentration of nitrile groups present in AN plasma. Significant changes in ED, and AN plasma-induced molecular fragmentation occur as the plasma conditions are varied. However, AcN plasma polymer chemistry is observed to be independent of RF frequency. Films deposited at 13.56 MHz RF power in continuous mode have higher concentrations of C-N linkages, with maximum in ED plasma-polymerized films. (c) 2007 Wiley Periodicals, Inc.