The present invention relates to a method for making an electrowetting display device comprising a plurality of picture elements and a first support plate and a second support plate. Each picture element comprises a space between the first support plate and the second support plate. The method comprises the steps of: providing the first support plate with an electrode structure; arranging an insulating layer on the electrode structure, the insulating layer having a thickness and a hydropobic surface facing the space; temporarily applying an electric field across the thickness of the insulating layer to reduce permanently the hydrophobicity of a predetermined area of the surface. The invention further relates to an electrowetting display device and a use of an area of reduced hydrophobicity in an electrowetting device.