Plate, Wire, Mesh, Microsphere, and Microtube Composed of Sodium Titanate Nanotubes on a Titanium Metal Template

Abstract

Sodium titanate nanotube/titanium metal composites were synthesized by hydrothermal treatment of titanium metals with various morphologies such as plate, wire, mesh, microsphere, and microtube at 160 degrees C in aqueous NaOH solution and by the subsequent fixation treatment by calcination at 300 degrees C. The surface of the composite was covered with sodium titanate nanotubes with a diameter of approximately 7 nm, and the core part of the composite was titanium metal phase. The raw titanium metal acts as a template or a morphology-directing agent of micrometer size or more to arrange the nanotubes as well as a titanium source for the formation of nanotubes. The concentration of titanium species increases in the reaction solution as the dissolution of titanium metal is accelerated by the reaction between titanium and OH-. Furthermore, with an increase in concentration of titanium species in the reaction solution, the titanium species are re-precipitated as sodium titanate nanotubes onto the titanium metal. Titanium metal with a large surface area and volume can form sodium titanate nanotubes on the surface of the titanium metal, though titanium metal with a small volume and surface area tends to dissolve with the hydrothermal treatment. Even in the synthesis using titanium metal with a small volume and surface area, sodium titanate nanotubes are formed and cover the surface of the titanium metal by adding another titanium metal as a source of titanium species in the reaction solution.

Synthesis of Titanate and Titanium Dioxide Nanotube Thin Films and Their Applications to Biomaterials

“…The thickness of this film is about 5 µm. This thickness was less than the 20 µm thickness of the Na-TNT film formed on the titanium plate when reacted singly (Yada et al, 2007). As the XRD pattern of the Co-Cr alloy surface countered to the titanium plate, a diffraction peak characteristic to titanate nanotube near 2θ = 10° as well as the peaks attributed to the Co-Cr alloy of the raw material were observed.…”

“…Therefore, the originality of our study is to use titanium metal as a morphology-directing material. In addition, we will report a novel procedure for fixation of Na-TNT thin film on titanium metal (Yada et al, 2007). As a result, the thickness of the sodium titanate nanotube thin film can be adjusted by changing the duration of the hydrothermal reaction and the obtained films are thicker than those reported in previous studies (Miyauchi et al, 2006;Tian et al, 2003).…”

“…Moreover, permanent fixation of the thin films onto the substrates is also doubtful. On the other hand, titanate and titanium dioxide nanotube thin films can also be formed on titanium metal by immersing titanium metal as a raw material into NaOH aqueous solution and then performing hydrothermal treatment (Miyauchi et al, 2006;Tian et al, 2003;Chi et al, 2007;Yada et al, 2007;Guo et al, 2007). The fabrication of titanate nanotube thin films using titanium metal plates was first reported by Tian et al (Tian et al, 2003).…”

“…In this chapter, first, we will report the synthesis and organization of sodium titanate nanotube (hereafter referred to as Na-TNT) of size larger than a micrometer, using various titanium metals with controlled shapes of a micrometer size including plate, wire with a diameter of a micrometer, mesh woven from the titanium wire, microspheres, and microtube (Yada et al, 2007). The titanium metal acts as a template for the organization as well as a titanium source.…”

“…Finally, we will describe the apatite-forming abilities of titanium compound nanotube thin films by comparing the apatite deposition behaviors of a sodium titanate nanotube thin film (Yada et al, 2007), a titanium dioxide nanotube thin film , and a silver nanoparticle/silver titanate nanotube nanocomposite thin film , in simulated body fluid (SBF) . In evaluating the in vivo apatite-forming ability or the osteoconductive property of a material, researchers commonly perform experiments in SBF ).…”