Antimicrobic low surface-free energy nanocomposite coatings

Abstract

A new type of silver nanoparticles containing coating based on inorganic-organic hybrid materials has been developed by the sol-gel technique to achieve antimicrobic properties. The formation of an inactive biofilm layer, which can block the antimicrobic effect, was reduced by decreasing the surface-free energy of the coating. Ag+ ions as effective oligodynamic components are generated by Ag nanoparticles with a size between 5-10nm. The Ag nanoparticles are produced during the drying and curing process. The investigation of the long-time release behavior of Ag+ ions show that the coating has oligodynamic properties for at least several month. The antimicrobic effect of the coating has been proved by inoculation with Gram negative bacterium E.coli. A low surface-free energy of about 19,5mN/m could be achieved by using side chain perfluorinated organo alkoxy silanes, which upconcentrate at the coating surface by thermodynamical reasons. Compared with uncoated samples the low surface-free energy of the coating lead to a reduction of biofilm adhesion of about 95%.