Coatings with self-cleaning properties

The issue of self-cleaning significantly gained popularity due to the work of Barthlott and coworkers on the so called “Lotos-Effect^®”. They found out, that the cleanliness of the Lotos leaves originates from a combined effect of surface topography and hydrophobicity. The symbol of the beautiful Lotos flower as well as the fascination of surfaces being cleaned without any manual activity, simply by a rain shower, has since then stimulated the fantasy of many researchers. Our vision is to copy this mechanism from mother nature and to implement it into coating systems in such a way, that conventional application techniques, e.g. spray-coating, can be applied without the necessity of further process steps like e.g. soft lithography. Three different approaches will be presented in this paper. Roughness and contact angle measurements have been used to quantify the self-cleaning properties.