Surface functionalization of PEEK films using photochemical routes

Two photochemical routes have been considered for the surface topologically defined functionalization of poly(ether ether ketone) (PEEK) films, based, respectively, on the covalent coupling of molecules protected with a photoclivable group (indirect way A), and on the photografting of various azide derivatives (direct way B). (4,5-Dimethoxy-2-nitrophenyl)methyl succinamate 3 could be coupled to the PEEK–OH film surface, under wet-chemistry conditions, but in rather low yield. 4-Azido-benzoic acid 9, 4-azido-tetrafluorobenzoic acid 6 and N-butyl-N′-(4-azidophenyl)thiourea 8 were grafted on the PEEK and PEEK–OH films surface, under mild photochemical conditions, in moderate to good yields. Attempts to obtain patterned surfaces with 4-azido-benzoic acid 9 and sodium 5-azido-naphthalene-1-sulphonate 10, under microlithographic conditions, failed.