Selective exposure of polymer substrates to extreme ultraviolet (EUV) radiation followed by graft polymerization of a second polymer is used to create patterns of polymer brushes. A key feature of this additive structuring process is the possibility to combine the properties of a polymer substrate in precisely p redefined regions with the properties of the grafted material. Styrene brushes were grafted onto poly(ethylene-alt-tetrafluoroethylene) (ETFE) substrates after exposure to synchrotron EUV radiation in an interference lithographic setup. The grafted chains are covalently bound to the surface, which allows physical or chemical post-processing without deterioration of the grafted structures. (C) 2004 American Vacuum Society.