Poly(vinylphosphonic acid) adsorbed onto chromium (III) oxide/hydroxide colloid as a model surface for polymer modified stainless steel

Abstract

Use of 316L stainless steel, with its highly stable chromium oxide passive layer, is ubiquitous in medical and food industry environments. There is little data in the literature on the ability of stainless steel to absorb multifunctional polymer layers which might impart different surface properties. Current research in this area focuses on layer by layer deposition and surface grafting techniques which are possibly too expensive and slow outside of the laboratory. The development of an absorbable polymer system is more favourable, but requires sufficiently adhesive functional groups which anchor the polymer to the surface and remain robust under aqueous conditions.A screen of likely binding groups showed that polyphosphonates were the most promising in terms of binding stability. To gain a better understanding of the binding mechanisms and adhesive tenacity of the trial polymers onto stainless steel a model surface of a chromium oxide colloid was used. In-situ attenuated total reflection infrared spectroscopy with real time monitoring of the formation of metal oxide surface complexes was used to follow the kinetics of the binding and desorption. This also provided meaningful quantitative data on complex formation, and possible identification of the binding modes present at the metal oxide surface groups.