Synthesis And Application Of Conducting Polymer Microcontainers

Nano/micrometer-sized materials, due to their unique properties different from those of their corresponding bulk materials, have many potential applications in microelectronics, micromachines, microchips and catalysis. Microstructured conductive polymer materials not only have the inherent trait of conducting polymers, but also have the functions of small size, which make them irreplaceable materials for applications in many aspects. In this dissertation, polypyrrole and poly(3,4-ethylenedioxythiophene) (PEDOT) microstructures were synthesized by direct electrochemical oxidation of their monomer in the aqueous solution on the indium tin oxide (ITO) glass electrode modified with multilayers poly (diallyldimethylammonium chloride) (PDDA) and poly (4-styrene sulfonic acid) (PSS). The microstructures have diameters in the range of 1~4μm. The formation mechanism of microstructures was also investigated. Furthermore, polypyrrole microstructure based on gas bubbles was also synthesized and its application in the biosensors was also investigated.1. Poly (3,4-ethylenedioxythiophene) (PEDOT) microstructures with diameters in the range of 1~4μm were synthesized by electropolymerization of EDOT in the aqueous solution of LiClO4 and tri(ethylene glycol) (TEG). The microstructures look like bowls and cups, and they were found standing upright on the surface of the electrodes in a high density of 106units cm2. The capillary effect of the microcups enhanced the hydrophilic property of the surface. Therefore, this technique developed a super-hydrophilic surface of conducting polymer. The mechanism was deduced to be as follows: EDOT was dispersed as microdroplets in the aqueous solution by sonication. Then, the microdroplets were assembled on the electrode and polymerized into microcups. The well-ordered microcups stand on the working electrode surface in a density of about 106 units cm-2. The ITO glass electrode was modified with multilayers and the PSS layers of the polyelectrolyte coating acted as the dopants of the resulting polymer and electrochemically catalyzed thepolymerization. Then the microdroplets were assembly onto the ITO glass and were elecrtopymerized into PEDOT microstructures by the catalysis of PSS layers.2. Polypyrrole(Ppy) microcontainers with diameters of 10μm were synthesized by electropolymerization of pyrrole in the aqueous solution of LiClO4. Pyrrole monomer was dispersed in a neutral aqueous solution as micro-droplets by sonication. The formation mechanism of Ppy microcontainers was similar with that of PEDOT. Different supporting electrolytes were studied to prepare the Ppy microstructure and the high density of 106~108 units cm-2 of microstructure was obtained.3. Ppy microstructures with diameters about 100μm can be synthesized by assembling gas bubbles on the electrode surface in the solution of (–)-camphorsulfonic acid. Based on Ppy microstructures, catalase/Ppy-microcontainers(Ppy-mc)/Pt electrode was fabricated as a sensor to detect the hydrogen peroxide and showed high sensitivity and selectivity.