The Mediated Electrodeposition of Polypyrrole on Aluminium Alloy

Abstract

The direct electrodeposition of conjugated polymers onto active metals such as aluminium and its alloys is complicated by the concomitant oxidation of the metal that occurs at the positive potential required for polymer formation/deposition. We have developed an approach that uses electron transfer mediation to reduce the deposition potential of polypyrrole on aluminium and aluminium alloy by nearly 500 mV, permitting film deposition from aqueous solution with nearly 100% current efficiency. The mediator used in this initial work was 4,5-dihydroxy-1,3-benzenedisulfonate (DHBDS, disodium salt), which also served as the dopant or counter ion in the polymer. To better understand the mediation process, a series of substituted benzene compounds have been explored for their mediating properties. From these studies, we conclude that both the hydroxyl and the sulfonate functionalities of DHBDS appear to play a role in the mediated electrodeposition at aluminium alloy. New mediators for the electrodeposition of polypyrrole on Al alloy are suggested.

Mott–Schottky analysis of aluminium oxide formed in the presence of different mediators on the surface of aluminium alloy 2024-T3

“…ICPs performance is greatly affected (Levine et al, 2005a) and understanding properties of oxide formed in ETM presence is necessary for successful ICPs deposition. The ETM influence of PPy deposition on Al alloy surface was described by Levine et al (2005b). The ETM influence on Al oxide formation is reported in current paper.…”

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

“…5 and shows a somewhat rougher surface than that obtained by mediated electrodeposition from aqueous solution. 18 Interestingly, the conductivity image reveals a rather uniform conductivity across the surface, the current averaging ca. 0.5 nA across the surface for a 50 mV bias potential.…”

“…[15][16][17] The mediator used most often in this earlier work was the disodium salt of 4,5-dihydroxy-1,3-benzenedisulfonate (DHDBS, also known as Tiron Ò ), which also served as the dopant or counter ion in the polymer, but other mediators appear promising and a mechanism has been proposed. 18 Galvanostatic electrodeposition of PPy in the presence of DHBDS leads to uniform, adherent, conducting, electroactive films. 15 Electrochemical atomic force microscopy studies 19 in combination with the potential-time curves obtained during galvanostatic electrodeposition of PPy 15 indicated that DHBDS mediates both the initial nucleation event (initial PPy deposition on the Al/Al 2 O 3 surface) and the film growth stage (PPy deposition on PPy).…”

Role of oxygen in the galvanic interaction between polypyrrole and aluminum alloy

“…We attribute this behavior to the electroactive dopant BDA (Tiron) which appears to play a role in the mechanism of O 2 reduction at the PPy-BDA film. We have previously described the ability of BDA to mediate the electrodeposition of PPy on AA [22][23][24][25].…”