Titanium oxide (TiO
2) was anodically formed on titanium from non-aqueous electrolyte containing glycerol and 0.5
wt.% ammonium fluoride (NH
4F). Oxidation was carried out for 30, 60, 120 and 240
min ...at potentiostatic 30
V with the bath being stirred using magnetic pellet. All the conditions produced amorphous nanotubes. They had an average diameter of 50–130
nm and length in the range of 1.2–1.9
μm. The porosity was in the range of 70–80%. Stirring of the glycerol-based electrolyte has proved to be advantageous in retaining the tubular structure and providing smooth tubes even at 30
V condition.
The coatings had surface roughness Ra lower than 0.5
μm, water wetting angles in the range of 58–84°. Increasing pore diameters increased the water wetting angles. All the coatings invariably showed poor tensile pull-off adhesion strengths. This poor adhesion is attributed to the stirring of the electrolyte.
TiO
2 was anodically formed on titanium from electrolyte containing 1M Na
2SO
4 and 0.5
wt.% NaF. Oxidation was carried out for 1
h at potentiostatic 20, 30 and 40
V from unstirred as well as stirred ...baths. At 20
V amorphous and nanotubular oxide is produced irrespective of the stirring conditions. Stirring increased the tubular length compared to the unstirred condition at 20
V. Oxidations at 30 and 40
V produced flat, crystalline anatase under both the bath conditions. A nanotubular network may be formed in the first 5
min and then anodic oxidation may occur laterally, perpendicular to the long-axis of the nanotubes.
TiO2 nanotube-type oxide film on Ti substrate has been fabricated using an electrochemical method, and the chemical bonding state, ultra-fine structures, and surface characteristics of the TiO2 ...nanotube layer have been investigated. The formation and growth of a self-organized nanotube layer can be achieved directly by anodization in NH4-containing electrolytes. The diameter, length, and wall thickness of the nanotube are significantly affected by anodizing conditions such as applied voltage, current density, and anodizing time. The length limiting factor of nanotube growth was found to be the diffusion of ionic species in the electrolyte. XRD investigations revealed that annealed nanotubes have anatase and rutile structure, and some Ti-peaks from the Ti substrate were observed. From the compositional analysis of TiO2 nanotubes layer using Energy Dispersive Spectroscopy (EDS), Ti, O, and P elements were obtained in the wall nanotube layer. For incorporated P-containing in the TiO2 nanotube layer, various chemical states were presented, which were revealed mostly in the forms of H2PO4, HPO4(2-), and PO4(3-).
Basic calcium phosphate (BCP) crystals have been associated with many diseases due to their activation of signaling pathways that lead to their mineralization and deposition in intra-articular and ...periarticular locations in the bones. In this study, hydroxyapatite (HAp) has been placed in a polysaccharide network as a strategy to minimize this deposition. This research consisted of the evaluation of varying proportions of the polysaccharide network, cellulose nanocrystals (CNCs), and HAp synthesized via a simple sol-gel method. The resulting biocompatible composites were extensively characterized by means of thermogravimetric analysis (TGA), powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), dynamic light scattering (DLS), zeta potential, and scanning electron microscopy (SEM). It was found that an nHAp = CNC ratio presented greater homogeneity in the size and distribution of the nanoparticles without compromising the crystalline structure. Also, incorporation of bone morphogenetic protein 2 (BMP-2) was performed to evaluate the effects that this interaction would have in the constructs. Finally, the osteoblast cell (hFOB 1.19) viability assay was executed and it showed that all of the materials promoted greater cell proliferation while the nHAp > CNC proportion with the inclusion of the BMP-2 protein was the best composite for the purpose of this study.
TiO
2
nanotube-type oxide film on Ti substrate has been fabricated using an electrochemical method, and the chemical bonding state, ultra-fine structures, and surface characteristics of the TiO
2
...nanotube layer have been investigated. The formation and growth of a self-organized nanotube layer can be achieved directly by anodization in NH
4
-containing electrolytes. The diameter, length, and wall thickness of the nanotube are significantly affected by anodizing conditions such as applied voltage, current density, and anodizing time. The length limiting factor of nanotube growth was found to be the diffusion of ionic species in the electrolyte. XRD investigations revealed that annealed nanotubes have anatase and rutile structure, and some Ti-peaks from the Ti substrate were observed. From the compositional analysis of TiO
2
nanotubes layer using Energy Dispersive Spectroscopy (EDS), Ti, O, and P elements were obtained in the wall nanotube layer. For incorporated P-containing in the TiO
2
nanotube layer, various chemical states were presented, which were revealed mostly in the forms of H
2
PO
4
, HPO
4
2-
, and PO
4
3-
.
Self-organized porous nanotubular TiO^sub 2^ was anodically formed on titanium in 1M Na^sub 2^SO^sub 4^ electrolyte containing 0.5 wt pct NaF. The oxidation was carried out for 0.5, 1, 2, and 4 hours ...at 20 V with the baths stirred using (1) magnetic pellet and (2) ultrasonic vibration. During the initial stages of oxidation, a barrier type of oxide film is formed, which gives rise to the formation of pores beneath it. With increasing time of oxidation, the pores self-organize to tubular structure. Of the two types of agitation studied, ultrasonics help in earlier complete removal of the barrier layer. The nanotubes have single-pore diameter of 50 to 90 nm under the magnetic pellet conditions and 55 to 110 nm under the ultrasonic agitation condition. The porosity was of the order of 24 to 30 pct for both types. The charges that have flown onto the coatings are greater under the ultrasonated condition. The as-oxidized coatings were amorphous for both types. The coatings obtained by using magnetic pellet had lower tensile adhesion strengths than those obtained using ultrasonic agitation. Heat treatment for 2 hours at 500 °C maintained the tubular morphology and converted the amorphous coatings to anatase TiO^sub 2^. These anatase containing coatings were analyzed for texture by X-ray pole figures, and it was found that (101) and (200) poles were randomly oriented. PUBLICATION ABSTRACT
Hydroxyapatite (HA) coatings were deposited on titanium substrates by electrophoretic deposition (EPD) at constant voltage and dynamic voltage, respectively. Various surface morphologies were ...observed under different type of voltages. Under a constant voltage of 20 V, a dense HA coating could be prepared. Under a constant voltage of 200 V, big HA particles were deposited and the coating was porous. Under a dynamic voltage, a continuous gradient HA coating could be obtained. HA coatings were characterized with a field emissionscanning electron microscopy (FE-SEM) and an X-ray diffraction (XRD). XRD indicated no significant HA decomposition when the coatings were sintered for 2 h at 800DGC. (D 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 78B: 373-377, 2006
TiO sub(2) nanotube-type oxide film on Ti substrate has been fabricated using an electrochemical method, and the chemical bonding state, ultra-fine structures, and surface characteristics of the TiO ...sub(2) nanotube layer have been investigated. The formation and growth of a self-organized nanotube layer can be achieved directly by anodization in NH sub(4)-containing electrolytes. The diameter, length, and wall thickness of the nanotube are significantly affected by anodizing conditions such as applied voltage, current density, and anodizing time. The length limiting factor of nanotube growth was found to be the diffusion of ionic species in the electrolyte. XRD investigations revealed that annealed nanotubes have anatase and rutile structure, and some Ti-peaks from the Ti substrate were observed. From the compositional analysis of TiO sub(2) nanotubes layer using Energy Dispersive Spectroscopy (EDS), Ti, O, and P elements were obtained in the wall nanotube layer. For incorporated P-containing in the TiO sub(2) nanotube layer, various chemical states were presented, which were revealed mostly in the forms of H sub(2)PO sub(4), HPO sub(4) super(2-), and PO sub(4) super(3-).
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