Optimizing Anodization Conditions for the Growth of Titania Nanotubes on Curved Surfaces

Abstract

Titania nanotubes (TNTs), fabricated by electrochemical anodization due to their outstanding properties, have been widely explored for solar cells, catalysis, electronics, drug delivery, biosensing, and medical implants. Rational design of the anodization conditions is the key to obtaining high quality TNTs that are well aligned and strongly adherent onto the underlying titanium substrate. With the development of many anodization procedures on a substrate with various shapes and sizes, catering to various applications, the mechanical stability of anodic layers is often neglected. Here we consider the factors that lead to unstable and poorly adherent nanotube arrays produced upon anodization of curved titanium surfaces. The role of electrolyte aging, water content, voltage/time of anodization, and the substrate dimensions were investigated for optimization of the fabrication of nanotubes on curved surfaces such as Ti wires. Finally, the most optimal fabrication procedure and anodization parameters are presented that yield high-quality nanotubes, which are stable and well-adherent on the underlying substrate.

Effect of phosphate/fluoride electrolytes on mass and dimensional stability of anodization bath manufactured by FDM

“…Electrochemical anodization technology can control the morphology, structure and chemical composition of TiO2 layers, leading to enhancement of the surface properties. By optimizing the process parameters of anodization, highly order and self arranged nanostructured surfaces can be developed [8][9][10][11]. Our recent results [1,[12][13][14] are in line with state of the art in this research field, and we bring also new contributions by being able to superimpose nanotubular layers over micro rough topographies [15].…”

Drug diffusion, integration, and stability of nanoengineered drug‐releasing implants in bone ex‐vivo

“…When anodizing curved surfaces of Ti substrates, cracks predictably occur on the anodic film, as a result of radial outgrowth of nanotubes and volume expansion of oxide (TiO 2 ) on metal surfaces . As we have previously reported, these cracks do not compromise the stability of the anodic film and actually allow for increased loading of therapeutics, albeit subject to burst release kinetics .…”

“…When anodizing curved surfaces of Ti substrates, cracks predictably occur on the anodic film, as a result of radial outgrowth of nanotubes and volume expansion of oxide (TiO 2 ) on metal surfaces. 25 As we have previously reported, these cracks do not compromise the stability of the anodic film and actually allow for increased loading of therapeutics, albeit subject to burst release kinetics. [14][15][16] Using an optimized fabrication procedure to engineer TNTs with fewer surface cracks, the amount and release kinetics of a particular drug could be tailored to achieve an optimal release profile, as presented in Figure 4.…”

Titanium wire implants with nanotube arrays: A study model for localized cancer treatment

“…The average thickness of the TNT layer was measured at approximately 9 mm (Fig. 1C), which was controlled by optimizing and selecting applied voltage settings to 75 V and anodisation time to 20 min [55]. Further high-resolution SEM analysis of top surface showed a densely packed array of nanotubes across the entire structure (Fig.…”