Abstract: A method of modifying the surface of a solid polymer substrate comprising the steps of a) generating radicals on the substrate surface by subjecting it to a gas plasma or by subjecting it to UV light, and b) treating the surface with a vapor of a monomer or a monomer mixture comprising cyano acrylate and/or isocyanate, where step b) starts before step a), simultaneously with step a), under step a), or follows immediately after step a), and a polymer substrate modified accordingly; a method of binding an organic binder material to a surface of a solid polymer substrate comprising the steps of modifying the surface of the substrate by said method, and bringing the organic material in contact with the surface of the substrate, and a polymer bonded to an organic material by the last mentioned method.