Poly (3-aminophenol) films have been grown electrochemically from solutions of 3-aminophenol at pH 7. These pinhole free films passivate the electrode surface and are less than 10 nm thick. The films are stable in I M solutions of sulphuric acid. However, they are rapidly degraded in solutions of sodium hydroxide. It is demonstrated that initially the polymer removal results in the creation of an electrode that exhibits the characteristics of a microelectrode ensemble. However, as further polymer is removed these characteristics are lost and response of the electrode resembles that of a large planar electrode. This chemical treatment of poly (3-aminophenol) films allows for the cost-effective production of microelectrode ensembles. (c) 2007 Elsevier Ltd. All rights reserved.