A method for the preparation of a medical device element, said method comprising the steps of: (i) providing a prefabricated shaped article and/or one or more layers of a thermoplastic substrate polymer; (ii) providing a coating composition comprising: (a) as the only polymer constituent(s), one or more hydrophilic polymer(s), and (b) one or more low molecular weight scaffolds having a plurality of photo-initiator moieties covalently linked thereto and/or covalently incorporated therein, wherein the photo-initiator moieties constitute 0.01-20 % by weight of the combined amount of the hydrophilic polymer(s) and the one or more low molecular weight scaffolds; (iii) extruding, injection moulding or powder coating the coating composition of step (ii) on the prefabricated shaped article and/or the thermoplastic substrate polymer of step (i) so as to provide the medical device element of said prefabricated shaped article and/or said substrate polymer having thereon a layer of said coating composition, wherein, when both of said prefabricated shaped article and said substrate polymer are present, said prefabricated shaped article has thereon a layer of said substrate polymer; (iv) irradiating the coating composition with UV or visible light so as to covalently cross-link said coating composition; wherein the prefabricated shaped article and/or one or more of the thermoplastic substrate polymers of step (i) comprising a polymer selected from the group of: Ethylene (Meth)acrylic Acid copolymer Ethylene - (Meth)acrylic Acid - Acrylic ester - terpolymer Ethylene (Meth)acrylic Acid ionomer; and wherein the medical device element is selected from tubes and catheters. (i) providing a prefabricated shaped article and/or one or more layers of a thermoplastic substrate polymer; (ii) providing a coating composition comprising: (a) as the only polymer constituent(s), one or more hydrophilic polymer(s), and (b) one or more low molecular weight scaffolds having a plurality of photo-initiator moieties covalently linked thereto and/or covalently incorporated therein, wherein the photo-initiator moieties constitute 0.01-20 % by weight of the combined amount of the hydrophilic polymer(s) and the one or more low molecular weight scaffolds; (a) as the only polymer constituent(s), one or more hydrophilic polymer(s), and (b) one or more low molecular weight scaffolds having a plurality of photo-initiator moieties covalently linked thereto and/or covalently incorporated therein, (iii) extruding, injection moulding or powder coating the coating composition of step (ii) on the prefabricated shaped article and/or the thermoplastic substrate polymer of step (i) so as to provide the medical device element of said prefabricated shaped article and/or said substrate polymer having thereon a layer of said coating composition, wherein, when both of said prefabricated shaped article and said substrate polymer are present, said prefabricated shaped article has thereon a layer of said substrate polymer; (iv) irradiating the coating composition with UV or visible light so as to covalently cross-link said coating composition; Ethylene (Meth)acrylic Acid copolymer Ethylene - (Meth)acrylic Acid - Acrylic ester - terpolymer Ethylene (Meth)acrylic Acid ionomer; and