Fabrication And Properties Of Titania Nanotube Arrays By Anodic Oxidation

TiO2 nanotube arrays were fabricated by anodic oxidation in electrolytes containing F+ in this paper. The morphology and phase of TiO2 nanotube were characterized by means of FE-SEM, XRD, TEM, respectively. The effects of anodic potential, environmental temperature and electrolyte composition on the nanotube morphology were investigated. The results indicated that TiO2 nanotube arrays can be regularly fabricated at the wide range of anodic voltage. Furthermore, pore size, wall thickness and length of nanotube arrays affected by anodic voltage. Fluorine concentration and environment temperature could affect the morphology of TiO2 nanotubes. The content of H2O affected the grown nanotube at high voltage. Longer nanotube can be growned in the modified electrolytes containing little (NH4)2SO4,NH4H2PO4 and (NH4)2TiF6, resprectively.The morphology of TiO2 nanotube array grown in DMF/glycerol mixed solution at low anodic voltage is reunion markedly. Then the anodic voltage increases, the morphology turns to regulation.The anatase and the rutile crystallites from amorphous as-fabricate TiO2 nanotube arrays can be formed inside the tube walls at different temperatures. Theirs tubular morphology can maintain higher than 700℃. After annealing at 450℃, the amorphous nanotubes changed into anatase type. After annealing at 600℃, part of anatase type changed into rutile. The thermal stability of TiO2 nanotube arrays grown in ethylene glycol based solution and DMF/glycerol mixed solution were lower than the sample grown in glycerol/water mixed solution.Moreover, the hydrophilicity, the bonding force between nanotube layer and titanium substance, biological activity and electro-chemical property of titania nanotube arrays were investigated.Titania nanotube arrays containg P and Ca were prepared after two-step treatment. Titania nanotube arrays with certain crystal are earily reaction to strong alkali conditions to Ca(OH)2, and then turn to four prism calcium titanate. The structure of nanotube arrays is ruined after reaction. But amorphous titania nanotubes array after calcification can still keep nanotubes array structure. Simulation test in vitro mineralization showed that Titania nanotube arrays containg P and Ca have better bioactivity. Further, the titania nanotube arrays tried to used as drug delivery, due to their hollow structure and good bonding force between nanotube layer and titanium substance. Some drugs, such as BSA, LYS and cephalothin, were loaded into titania nanotubes, the them were eluted for days. And adsorption and release of high length-diameter ratio of TiO2 nanotubes with bovine serum albumin array were studied.