Atomic force microscope studies of stainless steel: Surface morphology and colloidal particle adhesion

An atomic force microscope has been used to image four commercial stainless steel samples of widely differing surface finishes. Analysis of the images allowed quantification of surface roughness over different area scales, 50 x 50 mum, 10 x 10 mum and 1 x 1 mum. The atomic force microscope was also used to measure directly the adhesion of a single polymer latex particle (radius similar to5 mum) to the surface in solution using the colloid probe technique. It was found that the adhesion increased with decreasing roughness, except for the smoothest surface which exhibited very regular surface features on the area scale most relevant to adhesion of the particle (1 x 1 mum). There was a good correlation between the variability of adhesion over each surface and the corresponding variability in surface roughness. Measurements of this type should prove useful in the technical/economic choice of surface finish for a particular purpose. As the colloid probe has dimensions comparable to those of bacteria and yeast cells, such measurements should especially be of value in the selection of surface finish likely to minimise bioadhesion. (C) 2001 Kluwer Academic Publishers.