The electrodeposition of polypyrrole on Al alloy from room temperature ionic liquids

• Published in: JCT research Vol. 5; no. 3; pp. 327 - 334
• Main Authors: Nie, Jun, Tallman, Dennis E., Bierwagen, Gordon P.
• Format: Journal Article
• Language: English
• Published: Boston Springer US 01.09.2008; Springer
• Subjects: Applied sciences; Chemistry and Materials Science; Coatings. Paints, varnishes and inks; Corrosion; Corrosion and Coatings; Corrosion prevention; Exact sciences and technology; Film formation and curing, properties, testing; Industrial Chemistry/Chemical Engineering; Materials Science; Metals. Metallurgy; Polymer industry, paints, wood; Polymer Sciences; Surfaces and Interfaces; Thin Films; Tribology; Electrodeposition; Room temperature ionic liquids; Polypyrrole; Aluminum alloy; Imidazole derivatives; Electrical conductivity; Coating material; Electrical properties; Anticorrosive paint; Aluminium alloy; Experimental study; Electrochemical polymerization; Ionic liquid; Conducting polymers; Conjugated polymer; Electrochemical properties; Morphology; Pyrrole polymer
• ISSN: 1547-0091; 1935-3804; 2168-8028
• DOI: 10.1007/s11998-008-9084-x

The direct electrodeposition of conjugated polymers onto active metals such as aluminum and its alloys is complicated by the concomitant oxidation of the metal that occurs at the positive potential required for polymer formation/deposition. We previously described an approach that uses electron transfer mediation to reduce the deposition potential of polypyrrole (PPy) on aluminum and aluminum alloy by nearly 500 mV, permitting film deposition from aqueous solution with nearly 100% current efficiency. In this report, 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (EMIM + TFSI − ) has been successfully employed both as the growth medium and the supporting electrolyte for directly depositing uniform and conductive PPy coatings onto Al alloy 2024-T3 surface via a potentiodynamic technique. The depositions of PPy were carried out under cyclic voltammetric conditions from 0.3 M pyrrole in ionic liquid solutions. Film morphology was characterized by atomic force microscopy, optical microscopy, and scanning electron microscopy (SEM). Energy dispersive X-ray analysis and X-ray photoelectron spectroscopy verified that the TFSI − anion was incorporated into the polymer as the dopant ion. Thickness of the film was measured by SEM and film conductivity was determined by both a four-point probe technique and by conducting atomic force microscopy. Electrochemical activity of the film was assessed by cyclic voltammetry. Results from these preliminary studies will be reported.