Simultaneous electrochemical formation of Al2O3/polypyrrole layers (I): effect of electrolyte anion in formation process

We studied the capability of various kinds of sulfonate-based electrolytes to form a bilayered Al2O3/polypyrrole (PPy) film on an aluminum substrate i n aqueous solution. As electrolytes, we selected sodium p-toluenesulfonate (monovalent sulfonate), sodium naphthalene-trisulfonate (trivalent sulfonat e), poly(sodium 4-styrenesulfonate) poly(sodium vinylsulfonate) (sulfonate polymer), sodium n-dodecylbenzenesulfonate (SDBS), sodium. butylnaphthalene sulfonate(BNS), and sodium n-dodecylsulfate (SDS, surfactant sulfonate/sulf ate). Among the sulfonates we investigated, SDBS, BNS and SDS appeared to f orm a barrier-type Al2O3 layer with high coulombic efficiency in the absenc e of pyrrole. In the presence of pyrrole, anodization of these electrolytes resulted in the formation of Al2O3 and PPy layers, simultaneously. (C) 200 0 Elsevier Science Ltd. All rights reserved.