title: Measuring the ionic flux of an electrochemically actuated conducting polymer using modified scanning ion conductance microscopy.
abstract: We propose a modification of a scanning ion conductance microscope suitable for probing an electrode in an operating electrochemical cell. We demonstrate its use by measuring salt concentration variations near a conducting polymer electrode as the polymer is electrochemically oxidized and reduced. The electrochemical control circuit is opened to isolate the working electrode, at a frequency sufficiently high that the electrode capacitance maintains the electrode potential. The local solution conductivity variations are detected through the probe current during the open-circuit time. We demonstrate two-stage ion exchange during oxidation and reduction of poly(3,4-ethylenedioxythiophene) films that develops strongly with repeated cycling and is correlated with actuation changes. Spatial composition variations of the film, caused by redox current distribution over the surface, and electromigration to the probe tip, causing local solution composition changes, have clear and characteristic effects on the measured transients.
authors: Polymer Electronics Research Centre, Department of Chemistry, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand.
authors: Cosmin
authors: C
authors: Laslau
authors: David E
authors: DE
authors: Williams
authors: Bryon E
authors: BE
authors: Wright
authors: Jadranka
authors: J
authors: Travas-Sejdic