Microcontact printing using the spontaneous reduction of aryldiazonium salts

Patterning of aryl derivatives on graphitic carbon surfaces by printing with poly(dimethylsiloxane) stamps is described. The printing ink contained aryldiazonium salts which react spontaneously with the carbon substrate (pyrolyzed photoresist film) resulting in covalently attached modifiers. Printed surfaces were characterized using electrochemistry and scanning electron microscopy, and by generating water condensation figures. The method is very simple and versatile: both aqueous acid and DMF were shown to be suitable ink solvents and the diazonium salt could be printed directly from its synthesis solution. Surfaces patterned with nitrophenyl, aminophenyl, and caboxyphenyl groups were successfully prepared. Extension of the method to patterning other conducting and semiconducting substrates should be straightforward.