Good adhesion between chemically oxidized titanium and electrochemically deposited polypyrrole

• A method for producing extremely adhesive polypyrrole (Ppy) films is described. The electrochemical synthesis of Ppy on thin chemically pre-oxidized Ti layers produces a mechanically strong, shiny polymer film with extremely good adhesion. Adhesion of Ppy films on Ti metal without chemical pre-oxidation is very weak. Two multilayer systems are described with Ppy as an electrochemically active layer, chemically oxidized Ti (TixOy) as a thin adhesive layer, and either a Si-wafer or Al foil as a substrate. Ppy films survive more than 6000 reduction-oxidation cycles in aqueous electrolyte without delamination. The possible mechanisms of enhanced adhesion are discussed. Those are: (1) increased adhesion due to changes in the chemical composition and surface structure of the pre-oxidized Ti, (2) the possibility of the chemical oxidation of pyrrole on the metal surface in addition to the electrochemical polymerization, (3) the adsorption of pyrrole molecules onto pre-oxidized Ti surface by interaction with Ti hydroxides on surface, and (4) the simultaneous growth of TixOy and Ppy.

Keyword

TECHNOLOGY

TEKNIKVETENSKAP

Publication and Content Type

ref (subject category)

art (subject category)