Common mechanism for helical nanotube formation by anodic polymerization and by cathodic deposition using helical pores on silicon electrodes

Abstract

We report that platinum-assisted chemical etching formed self-organized helical pores in silicon substrates can be utilized as platforms for the electrochemical production of nanohelices of conducting polymers (polypyrrole) and metals (gold). Surprisingly, the nanohelices thus created are tubes although the polymerization and deposition were carried out by anodic and cathodic reactions, respectively. Based on our results, we propose a common mechanism for the formation of tubular nanohelices by both anodic polymerization and cathodic deposition through the accumulation of reactants in microporous silicon which covers the wall surface of the helical pores.