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DEPOSITION OF POLYANILINE-POLYPYRROLE COMPOSITE COATINGS ON ALUMINUM

by AKUNDY, GOURI

Abstract (Summary)
The electrodeposition of polyaniline, polypyrrole and their composite coatings on aluminum was successfully performed by cyclic voltammetry using oxalic acid as the electrolyte. Electrodeposition parameters such as scan rate and the number of cycles (reaction time) were varied. At longer reaction times, the characteristic peak currents corresponding to the formation of the homopolymers were seen in their respective cyclic voltammograms. The infrared spectra of the coatings showed the presence of aluminum oxalate passive film at short cycles. At longer cycles, the infrared spectra of the composite coatings showed both the absorption bands of polyaniline and polypyrrole. The scanning electron micrographs revealed globular morphology for polyaniline, microspheroidal structure for polypyrrole and flaky morphology for the composite. The behavior of the cyclic voltammograms at longer cycles revealed a quasi-reversible charge transfer mechanism. A chemical reaction preceding irreversible charge transfer was observed at shorter cycles. The adhesion of the composite coatings to the aluminum substrate was determined by lap shear tests according to an ASTM standard procedure D-1002-94. For a high aniline concentration (90%) in the reaction mixture, higher adhesion (12.5 MPa) values were obtained in comparison with the control (7.74 MPa). With a high concentration of pyrrole (90%) in the reaction mixture, good adhesion results (12.09 MPa) were obtained at shorter reaction times (30 sec).
Bibliographical Information:

Advisor:

School:University of Cincinnati

School Location:USA - Ohio

Source Type:Master's Thesis

Keywords:conduting polymers polyaniline polypyrrole composite electrochemical polymerization

ISBN:

Date of Publication:01/01/2001

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