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Fabrication of complete titania nanoporous structures via electrochemical anodization of Ti.

Ali G, Chen C, Yoo SH, Kum JM, Cho SO - Nanoscale Res Lett (2011)

Bottom Line: However, a complete titania nano-porous (TNP) structures are obtained when the second anodization is conducted in a viscous electrolyte when compared to the first one.The average pore diameter is approximately 70 nm, while the average inter-pore distance is approximately 130 nm.These TNP structures are useful to fabricate other nanostructure materials and nanodevices.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology (KAIST), 373-1 Guseong, Yuseong, Daejeon 305-701, Republic of Korea. socho@kaist.ac.kr.

ABSTRACT
We present a novel method to fabricate complete and highly oriented anodic titanium oxide (ATO) nano-porous structures with uniform and parallel nanochannels. ATO nano-porous structures are fabricated by anodizing a Ti-foil in two different organic viscous electrolytes at room temperature using a two-step anodizing method. TiO2 nanotubes covered with a few nanometer thin nano-porous layer is produced when the first and the second anodization are carried out in the same electrolyte. However, a complete titania nano-porous (TNP) structures are obtained when the second anodization is conducted in a viscous electrolyte when compared to the first one. TNP structure was attributed to the suppression of F-rich layer dissolution between the cell boundaries in the viscous electrolyte. The structural morphologies were examined by field emission scanning electron microscope. The average pore diameter is approximately 70 nm, while the average inter-pore distance is approximately 130 nm. These TNP structures are useful to fabricate other nanostructure materials and nanodevices.

No MeSH data available.


Related in: MedlinePlus

FESEM images of TiO2 nanotubes fabricated in 0.5 wt% aqueous-based HF electrolyte via second-step anodization: (a) top surface view at low magnification, (b) top surface view at high magnification, (c) top surface view of patterned Ti-substrate anodized for 10 min, and (d) cross-sectional view.
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Figure 4: FESEM images of TiO2 nanotubes fabricated in 0.5 wt% aqueous-based HF electrolyte via second-step anodization: (a) top surface view at low magnification, (b) top surface view at high magnification, (c) top surface view of patterned Ti-substrate anodized for 10 min, and (d) cross-sectional view.

Mentions: The surface and the cross-sectional topologies of TiO2 nanotubes obtained after the second-step anodization in HF-containing aqueous electrolyte is shown in Figure 4. The top surface view of the TiO2 nanotubes at a low- and a high-magnification is shown in Figure 4a,b, respectively. Irregular shape of pores can be seen clearly in the images. These images show that the honeycombs-like pre-patterned morphology and the hexagonal shape geometry of the individual nanodimples (Figure 2d) are completely destroyed after the second-step anodization unlike EG-based electrolyte. This is due to the strong dissolution power of the HF-based electrolyte where TiO2 dissolution is very fast compared to the EG electrolyte [28]. The dissolution power of the HF-based electrolyte is evident from Figure 4c, which shows the top surface morphology of the pre-patterned Ti-substrate after 5-10 min of anodization. Even after a very short anodizing time, the original pre-patterned hexagonal shape morphology of Ti-substrate (Figure 2d) is completely vanished and a new shape morphology emerged. The new morphology is retained in most of the area, however, in some places (marked area in Figure 4a), the nanopores are dissolved and led to the covering of TNT at the top surface. This is attributed to the extended anodization in HF-based electrolytes. The surface image (Figure 4b) and the cross-sectional image (Figure 4d) reveal the formation of a thin nanoporous layer on the top surface of TNT and show the roughness of TNT walls. Some of the nanopores covering two and more nanotubes can also be seen, which confirms the formation of a nanoporous layer on the top surface of TNT. The roughness of the nanotube walls is ascribed to water in the electrolyte [21].


Fabrication of complete titania nanoporous structures via electrochemical anodization of Ti.

Ali G, Chen C, Yoo SH, Kum JM, Cho SO - Nanoscale Res Lett (2011)

FESEM images of TiO2 nanotubes fabricated in 0.5 wt% aqueous-based HF electrolyte via second-step anodization: (a) top surface view at low magnification, (b) top surface view at high magnification, (c) top surface view of patterned Ti-substrate anodized for 10 min, and (d) cross-sectional view.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211420&req=5

Figure 4: FESEM images of TiO2 nanotubes fabricated in 0.5 wt% aqueous-based HF electrolyte via second-step anodization: (a) top surface view at low magnification, (b) top surface view at high magnification, (c) top surface view of patterned Ti-substrate anodized for 10 min, and (d) cross-sectional view.
Mentions: The surface and the cross-sectional topologies of TiO2 nanotubes obtained after the second-step anodization in HF-containing aqueous electrolyte is shown in Figure 4. The top surface view of the TiO2 nanotubes at a low- and a high-magnification is shown in Figure 4a,b, respectively. Irregular shape of pores can be seen clearly in the images. These images show that the honeycombs-like pre-patterned morphology and the hexagonal shape geometry of the individual nanodimples (Figure 2d) are completely destroyed after the second-step anodization unlike EG-based electrolyte. This is due to the strong dissolution power of the HF-based electrolyte where TiO2 dissolution is very fast compared to the EG electrolyte [28]. The dissolution power of the HF-based electrolyte is evident from Figure 4c, which shows the top surface morphology of the pre-patterned Ti-substrate after 5-10 min of anodization. Even after a very short anodizing time, the original pre-patterned hexagonal shape morphology of Ti-substrate (Figure 2d) is completely vanished and a new shape morphology emerged. The new morphology is retained in most of the area, however, in some places (marked area in Figure 4a), the nanopores are dissolved and led to the covering of TNT at the top surface. This is attributed to the extended anodization in HF-based electrolytes. The surface image (Figure 4b) and the cross-sectional image (Figure 4d) reveal the formation of a thin nanoporous layer on the top surface of TNT and show the roughness of TNT walls. Some of the nanopores covering two and more nanotubes can also be seen, which confirms the formation of a nanoporous layer on the top surface of TNT. The roughness of the nanotube walls is ascribed to water in the electrolyte [21].

Bottom Line: However, a complete titania nano-porous (TNP) structures are obtained when the second anodization is conducted in a viscous electrolyte when compared to the first one.The average pore diameter is approximately 70 nm, while the average inter-pore distance is approximately 130 nm.These TNP structures are useful to fabricate other nanostructure materials and nanodevices.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology (KAIST), 373-1 Guseong, Yuseong, Daejeon 305-701, Republic of Korea. socho@kaist.ac.kr.

ABSTRACT
We present a novel method to fabricate complete and highly oriented anodic titanium oxide (ATO) nano-porous structures with uniform and parallel nanochannels. ATO nano-porous structures are fabricated by anodizing a Ti-foil in two different organic viscous electrolytes at room temperature using a two-step anodizing method. TiO2 nanotubes covered with a few nanometer thin nano-porous layer is produced when the first and the second anodization are carried out in the same electrolyte. However, a complete titania nano-porous (TNP) structures are obtained when the second anodization is conducted in a viscous electrolyte when compared to the first one. TNP structure was attributed to the suppression of F-rich layer dissolution between the cell boundaries in the viscous electrolyte. The structural morphologies were examined by field emission scanning electron microscope. The average pore diameter is approximately 70 nm, while the average inter-pore distance is approximately 130 nm. These TNP structures are useful to fabricate other nanostructure materials and nanodevices.

No MeSH data available.


Related in: MedlinePlus