| abstract |
The present invention provides a method for coating a surface of a 3-dimensional substrate having a non-planar surface geometry, in particular a substrate comprising at least one lumen or cavity, with a highly liquid-repellent and/or microorganism-repellent nanofilament coating comprising at least the following steps: a) contacting the substrate surface or a part thereof, in particular including the inner surface of any lumen or cavity thereof, for a predetermined period of time with an activating agent to generate oxygen-comprising functional groups, or to provide an absorbed water film or adsorbed water drops on said surface. b) contacting the substrate surface obtained after step a) for a predetermined period of time with a siliconizing agent to form a coating of liquid-repellent and/or microorganism-repellent silicone nanofilaments on said substrate surface or a part thereof, wherein the siliconizing agent comprises at least one substituted silane compound capable to react with oxygen-comprising groups or preabsorbed water film or water drops on said substrate surface and also to undergo a polysiloxane reaction with water to form covalently bonded silicone nanofilaments on said substrate surface or part thereof. In some preferred embodiments, the activation agent in step a) is selected from various oxidizing agents, in particular reagents including hydrogen peroxide and a catalyst capable to provide hydroxyl radicals in a Fenton's reaction, or from water film or water drops providing agents, in particular a mixture of a C1-C7 alkanol and water, or a humid gas, such, as air, nitrogen or oxygen, having a relative humidity of more than 60%. A further aspect of the invention relates to a 3-dimensional substrate having a non-planar surface geometry, in particular a substrate comprising at least one lumen or cavity having a high aspect ratio, with a highly liquid-repellent and/or microorganism-repellent coating comprising silicone nanofilaments, in particular on the inner surface of said lumen or cavity or at least a part thereof, which is obtainable by the method as described above. |