Electrochemical properties of mono-particle-layer films of polyaniline-coated latex microspheres

Latex particles with the structure of a polystyrene core and a polyaniline shell were synthesized. They were nearly mono-dispersed spheres 1.62 μm in diameter. The aqueous suspension of the latex particles was spread on a glass substrate and dried in a mono-particle layer. The arrangement of the spread particles depended on the concentrations of the latex, those of the surfactant, and drying speed. The particles were also arranged on a platinum electrode in a mono-particle layer at a very slow drying speed although the particles were likely to gather at the boundary between the platinum and the insulating wall. The cyclic voltammograms of the mono-particle layer were similar to those of electrochemically polymerized films and of the film prepared by spreading and drying the polyaniline-dissolved pyrrolidone. The peak currents at high scan rates deviated downward from a linear relation with the scan rate. The mono-particle layer was inserted into tetrahydrofuran to remove the core-polystyrene. The resulting film covered the electrode surface smoothly. Its voltammetric peak current was almost proportional to the scan rate, as was observed at electropolymerized films.