Initiation of Organized Nanopore/Nanotube Arrays in Titanium Oxide II. Nanopore Size and Spacing

In a series of two papers. a mechanism is proposed to describe the initiation of organized arrays of nanopores and nanotubes formed via anodization of titanium. Part I describes the mechanism of initiation, based on the instability of the planar oxide/electrolyte interface. and develops a criterion for the initiation of nanopores, while the present paper Uses this planar interface instability criterion to calculate the size/spacing, of nanopores. To facilitate the calculation. the destabilized interface is modeled by a series of sine waves. representing, surface perturbations. Because the growth rates of the sine waves are a function of their wavelengths, the spacing of the ultimate array of nanopores and nanotubes is related to the wavelength of the fastest-growing perturbation. The proposed mechanism explains the transition from disorganized to organized and the influence of voltage on pore spacing and size. (C) 2008 The Electrochemical Society. [DOI: 10.1149/13049342] All rights reserved.