An article, comprising a substrate and a polymer film attached to the substrate is provided, the polymer film comprising a first layer of a first polymer functionalized by a first functionalization compound covalently bound to said first polymer and bearing at least one catecholic group being present on a surface of the first layer. The polymer film is a layered film, a top layer of which is formed by the first layer, the layered film comprising at least one further layer of at least one further polymer functionalized by a further functionalization compound covalently bound to said further polymer and bearing at least one catecholic group being present on a surface of the at least one further layer, wherein an average ratio of catecholic groups per polymer molecule is equal to or less than 1 in case of the first polymer and greater than 1 in case of the further polymer.
