Formation of Ultrathin Polypyrrole (PPY) Films on Alumina Particles Using Adsorbed Hexanoic Acid as a Template

• Published in: Langmuir Vol. 16; no. 10; pp. 4424 - 4429
• Main Authors: Cho, Gyoujin, Glatzhofer, Daniel T., Fung, Bing M., Yuan, Wei-Li, O'Rear, Edgar A.
• Format: Journal Article
• Language: English
• Published: American Chemical Society 16.05.2000
• ISSN: 0743-7463; 1520-5827
• DOI: 10.1021/la990247d

Thin films of polypyrrole (PPY) were deposited on alumina particles using hexanoic acid adsorbed on the particles as a template. The formation of the template on alumina was confirmed through studies of the adsorption of hexanoic acid at various pH values. The adsorption results could be fitted to the Langmuir adsorption isotherm at pH levels of 5 and 6, indicating monolayer adsorption. Solubilization studies of pyrrole on alumina particles with adsorbed hexanoic acid in aqueous solution at pH levels of 3, 4, 5, and 6 showed 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 surface 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 coated by polypyrrole films. The contact conductivity of these PPY−alumina composites (4.7 × 10-2 s·cm-1) is more than 3 times that of a pure polypyrrole powder, even with a very low amount (12 wt %) of polypyrrole incorporated onto alumina.