Electrochemistry at ultrathin polyelectrolyte films self-assembled at planar gold electrodes

Planar positively-charged gold electrode surfaces were modified by consecut ive adsorption of poly(styrene sulfonate), PSS, and protonated poly(allyl a mine), PAH. By varying the sulphuric acid concentration in the PAH adsorpti on solution it was possible to obtain films with two different thicknesses. The permeability of the two types of self-assembled films was probed by st udying the cyclic voltammetric response with two electroactive species in t he supporting electrolyte; i.e. an anion, Fe(CN)(6)(4-) and a cation, Os(bi py)(3)(3+). Electrochemical impedance spectroscopy was also employed in the characterisation of the films. (C) 1999 Elsevier Science Ltd. All rights r eserved.