Fabrication And Electrochemistry Of Two-dimensional Ordered Cavities On Electrode Surfaces

Monodisperse micrometer polystyrene particles were prepared by emulsion polymerization. The polystyrene particles were uniformly assembled into a two-dimensional structure on indium-doped tin oxide (ITO) electrodes. The factors that may affect the assembly of the polystyrene particles, including the particle concentration, ethanol/water proportion, were investigated.The uniformly assembled polystyrene particles on the ITO electrode were further used as a template for the electrochemical deposition of zinc oxide (ZnO). After the removal of the templating polystyrene particles, an array of micro-cavities of ZnO was obtained. Due to the resistance gradient of the ZnO cavity structure, the ZnO cavity exhibits a confinement effect on the electrochemical reactions, making the electrode to function as an array of the"soft"microelectrodes. This was verified by the cyclic voltammetric behavour of the ZnO cavity modofied electrode in the Fe(CN)63- - KCl solution. The electrochemical reduction of silver cations on the ZnO cavity modofied electrode the ZnO cavity modofied electrode leads to the formation of the silver nanoparticles localized at the bottom of the ZnO cavities.With the template of the ordered structure of the polystyrene particles, the array of tungsten trioxide (WO3) micro-cavities was also prepared on an ITO electrode by electrodeposition. Polyaniline was then electrochemically deposited into the WO3 cavities. The UV-vis spectra obtained at different electrode potentials indicate that the cavity structure of the WO3 can markedly affect the electrochromism of polyaniline.