Formation of ultrathin polypyrrole (PPY) films on alumina particles using adsorbed hexanoic acid as a template

Thin films of polypyrrole (PPY) were deposited on alumina particles using h exanoic acid adsorbed on the particles as a template. The formation of the template on alumina was confirmed through studies of the adsorption of hexa noic acid at various pH values. The adsorption results could be fitted to t he Langmuir adsorption isotherm at pH levels of 5 and 6, indicating monolay er adsorption. Solubilization studies of pyrrole on alumina particles with adsorbed hexanoic acid in aqueous solution at pH levels of 3, 4, 5, and 6 s howed that a large amount of pyrrole was condensed at the interface at a pH level of 4, and subsequent polymerization can be carried out at the surfac e of alumina. In the atomic force microscopy studies, the morphology of the resulting PPY on alumina particles showed multigranular images similar to those of pure polypyrrole films and all alumina particles were completely c oated by polypyrrole films. The contact conductivity of these PPY-alumina c omposites (4.7 x 10(-2) s.cm(-1)) is more than 3 times that of a pure polyp yrrole powder, even with a very low amount (12 wt %) of polypyrrole incorpo rated onto alumina.