Ke Chunhai, Ma Jingyun, Ni Jiahua, Peng Zhaoxiang
Ningbo Medical Center, Lihuili Hospital, Ningbo University, Ningbo, China.
Ningbo Regen Biotech, Co., Ltd., Ningbo, China.
Ann Transl Med. 2023 Jan 15;11(1):18. doi: 10.21037/atm-22-6510. Epub 2023 Jan 12.
Research on the growth mechanism of titanium dioxide (TiO) nanotube arrays fabricated by anodic oxidation is essential to achieve artificial control of the microstructure and to expand their applications. In our previous work, we reported the preparation of highly ordered large-diameter double-wall TiO nanotube arrays prepared by high voltage anodization.
In this paper, we observed and analyzed the initial growth process of large-diameter double-wall TiO nanotube arrays anodized at 120 V in ethylene glycol electrolyte containing aluminum fluoride (NHF) and water (HO), such as the evolution of surface and cross-sectional morphologies, the influence of current density on growth rate, the transition process from nanoholes to nanotubes, and the evolution of dimples on the remaining substrate.
On the basis of our observations and inspirations from the existing viewpoints, we established growth models of large-diameter double-wall TiO nanotube arrays corresponding to different growth stages to explain the growth process. The growth rate of anodic oxide film changes accordingly with the current density. The compact anodic oxide film formed initially actually contains outer layer and inner layer, with no obvious interface between them. Then, the bottom even levels of the inner layer and outer layer bulge towards the substrate and become individual hemisphere-like structures. The inner layer becomes the outer wall, and the outer layer becomes inner wall. Eventually, V-shaped large-diameter and double-wall TiO nanotube arrays form.
The results presented in this work are significant and provide a better understanding of the growth mechanism of large-diameter double-wall TiO nanotube arrays anodized by high voltage.
研究阳极氧化制备的二氧化钛（TiO）纳米管阵列的生长机制对于实现微观结构的人工控制并拓展其应用至关重要。在我们之前的工作中，我们报道了通过高压阳极氧化制备的高度有序的大直径双壁TiO纳米管阵列。
在本文中，我们观察并分析了在含有氟化铝（NHF）和水（HO）的乙二醇电解液中于120 V电压下阳极氧化的大直径双壁TiO纳米管阵列的初始生长过程，如表面和横截面形貌的演变、电流密度对生长速率的影响、从纳米孔到纳米管的转变过程以及剩余基底上凹坑的演变。
基于我们的观察以及从现有观点获得的启发，我们建立了对应不同生长阶段的大直径双壁TiO纳米管阵列的生长模型来解释生长过程。阳极氧化膜的生长速率随电流密度相应变化。最初形成的致密阳极氧化膜实际上包含外层和内层，它们之间没有明显界面。然后，内层和外层的底部向基底凸起并变成单独的半球状结构。内层成为外壁，外层成为内壁。最终，形成V形大直径双壁TiO纳米管阵列。
本文给出的结果意义重大，能更好地理解高压阳极氧化的大直径双壁TiO纳米管阵列的生长机制。
