Potential-induced switching of electrical contact by controlling droplet shapes at hydrophilic/hydrophobic interfaces

Asymmetrical deformation of an aqueous electrolyte droplet bridging two bipyridinium-modified Au-electrodes is achieved upon the application of voltages resulting in the selective reduction and oxidation of the bipyridinium units on the two electrodes. The different contact angles at the right and left sides of the droplet originate from the electrochemically controlled changes of the wetting properties of the modified electrodes. The reversible and repeatable formation of an electrolytic contact between a side Pt-wire electrode and the respective bottom Au-electrode is controlled by the voltage applied between the two bottom Au-electrodes. (C) 2003 Elsevier B.V. All rights reserved.