Abstract
Surface roughness also in the nanoscale range is one of the most important parameters governing the interaction of solid surfaces with their surrounding environment, e.g. in biomedical applications. In this contribution we employ a novel two-step vacuum process for the fabrication of nanorough coatings that combines deposition of nano-clusters with deposition of thin films by low-pressure plasma methods.
In the first step, thin film of metal or plasma polymerized nano-clusters is deposited on a smooth surface by means of gas aggregation nano-cluster sources utilizing water cooled planar magnetrons. It is shown that a wide range of surface roughness may be reached (from root-mean-square roughness of about 1 to more than 100 nm) either by the variation of the nano-cluster sizes or by changing the surface density of nano-clusters.
Films prepared in the first step are subsequently overcoated by a thin layer of plasma polymer or metal deposited by magnetron sputtering. This procedure allows an independent control of chemical composition of the surface, which is given solely by the chemical composition of the overlayer film, and surface roughness, which is determined by the properties of underlaying nano-cluster film.
Possible application of the surfaces prepared as mentioned above for biomedical purposes is briefly discussed.