Influence of the microstructure of sputtered Ti films on the anodization toward TiO2 nanotube arrays

[Display omitted] •Ti film density (>3.7 g/cm3) is crucial for microstructure affecting TNTs formation.•Multiple microstructures of the Ti films were created using magnetron sputtering under controllable parameters.•Electron aggregation theory explains dense Ti film benefits TNTs formation after anodization. The microstructure of sputtered Ti films plays a crucial role in the formation of TiO2 nanotube arrays (TNTs) via anodization. Magnetron sputtering under controllable parameters was used to create diverse microstructures of Ti films, followed by anodization in an ethylene glycol-based electrolyte. The relationship between the microstructures of Ti films and the resulting TiO2 layers was analyzed, and the film density was identified as the key microstructure affecting the TNTs formation. The electron aggregation theory explained why denser Ti films facilitate TNTs formation, and confirmatory experiments were performed to validate this theory..