Membranes anodic alumina

A) anodic alumina membrane (pore diameter (E) inclusion of the hydrophobic carriers 5 or 6. 

A similar approach for the production of hydrothermal carbon nanotubes is the hydrothermal carbonization of glucose in the macrochannels of anodic alumina membranes [16]. Depending on the pore size of the membrane different hollow hydrother-... 

Terms such as symmetric and asymmetric, as well as microporous, meso-porous and macroporous materials will be introduced. Symmetric membranes are systems with a homogeneous structure throughout the membrane. Examples can be found in capillary glass membranes or anodized alumina membranes. Asymmetric membranes have a gradual change in structure throughout the membrane. In most cases these are composite membranes... 

Hgure 3.9. Dynamic pore size distributions of (a) two sol-gel alumina membranes and (b) two anodized alumina membranes (Fain 1990). 

Confined reactions have been used to control the size of MoS2 nanotubes. For example, MoS2 nanotubes have been grown in the voids of an anodic alumina membrane, by decomposing (NH,)2MoS4 inside the pores of the membrane.31 The membrane is dissolved by treatment with alkali to yield free tubes. This method yields large diameter MoS2 nanotubes. 

Pbres of anodic alumina have been used for the growth of coaxial nanotubes of Ti02 sheathed SiO 92 Electrochemical deposition in the pores of a polymeric alumina membrane generates arrays of Ti02 nanotubes. R>r the coaxial nanotubes, the SiOj nanotubes are first grown inside the pores of the anodic alumina membrane The Ti02 nanotubes are then grown inside the SiOj nanotubes. The existence of Ti-O-Si bonds in the amorphous sheaths is believed to play a role in the formation of these composite nanotubes... 

Trocha and Koros [1994] applied a diffusion-controlled caulking procedure with colloidal silica to plug large pores or defects in ceramic membranes. An important feature of this proc ure is the proper selection of the colloid particle size to eliminate or reduce large, less selective pores while minimizing deposition in the small desirable pores. The technique has b n successfully proven with anodic alumina membranes (having the majority of the pores about 2(X) nm in diameter) using 10-20 nm silica colloids. 

Molecularly bonded silver membranes have also been used to purify aggressive HPLC solvents [Minneci and Paulson, 1988]. Similar to the anodic alumina membranes, silver membranes are preferred for this application due to the following reasons high chemical and thermal stabilities leading to no or negligible amount of dissolved or leached membrane constituents in the solvents. 

It is interesting to note that, due to its uniform and nearly straight pore structure, planar anodic alumina membranes have been used as the probes for monitoring catalyst deactivation at the single pore level [Nourbaksh et al, 1989a]. The nearly idealized structure is suitable for various surface analysis techniques such as scanning and transmission election microscopy and associated EDX and XPS to be applied to fresh as well as spent catalysts. In the case of hydrotreating of crude-derived heavy oils, catalyst... 

P.P. Mardilovich, PV. Kurman. A.N. Govyadinov ei. al.. The gas permeability of anodic alumina membranes with palladium-ruthenium alloy layer, Russian J. Phys. Chem., in press. 

Anodized Alumina Membrane as a Mask for Physical Vapor Deposition... 

Highly ordered Ti02 nanowire (TN) arrays were prepared [211] in anodic alumina membranes by a sol-gel method. The TNs are single crystalline anatase phase with uniform diameters around 60 nm. At room temperature, photoluminescence measurements of the TN arrays show a visible broadband with three peaks, which are located at about 425, 465, and 525 nm that are attributed to self-trapped excitons, F, and F+ centers, respectively. 

Sunseri. C.. Spadaro, C., Piazza, S., and Volpe, M. 2006. Porosity of anodic alumina membranes from electrochemical measurements. Journal of Solid State Electrochemistry 10,... 

Winkler, B.H. and Baltus, R.E., Modification of the surface characteristics of anodic alumina membranes using sol-gel precursor chemistry, 7. Membr. Sci., 226, 75, 2003. 

Synthesis of arrays of BiTe nano-wires by electrodeposition has been studied by different authors [63-66]. Li et al. employed pulsed electrodeposition into the nanochannels of porous anodized alumina membranes to fabricate nano-wire arrays of Be TCj [63]. The anodized alumina membrane with the pore sizes of about 40 and 60 nm were used. A 200 nm thick layer of Au film was sputtered onto one side of the anodized alumina membrane to serve as the working electrode in a two-electrode plating cell, and a graphite plate was used as the counter-electrode. 

We present experimental results on light scattering by porous anodic alumina membranes and show that probability of light scattering has a maximum in the direction along pores. 

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