TiO₂NTs bio-inspired coatings: revisiting electrochemical, morphological, structural, and mechanical properties

By altering some synthesis variables, the morphology and structural properties of anodic TiO₂nanotube arrays (TiO₂NTs) can be tailored to a specific application. This study aims to investigate the effect of electrolyte-containing ions from human plasma and annealing temperature on structural, morphological, and mechanical parameters of TiO₂NTs films, targeting its potential biomedical applications. Bio-inspired TiO₂NTs were grown from Ti_cpand its Ti6Al4V alloy by potentiostatic anodization in the recently developed SBF-based electrolyte, maintained at 10 °C and 40 °C. The thermal investigation was performed by TGA/DSC and used to define the phase transition temperatures used for annealing (450 °C and 650 °C). Morphological and structural parameters were evaluated by FE-SEM, XRD, contact angle measurements, and nanoindentation. Results show that self-organized as-formed TiO₂NTs were grown under all synthesis conditions with different wettability profiles for each substrate group. At 450 °C annealing temperature, the beginning of nanostructures collapse starts, becoming evident at 650 °C. The nanoindentation characterization reveals that both electrolyte and thermal annealing exhibited low effects on the hardness and Young's modulus. The tailoring of specific properties by different synthesis conditions could allow the individualization of treatments and better performancein vivo.