Anodized aluminum oxide membranes

Many strategies have been ingeniously implemented to fabricate complicated nanostructures based on the AAO templates. For example, hexagonally ordered Ni nanocones have been fabricated using an a porous AAO template where the pores are of a cone shape [135]. The conical AAO film was found to exhibit hexagonal order with a period of 100 nm. The Ni nanocones and the surface morphology of the nanoconical film exhibit the same periodic structure of the template as shown in Fig. 1.11. 

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Figure 2.14. The structure of an anodized aluminum oxide membrane (Anopore) as shown in Anotec Separations (1986) (a) is a homogeneous membrane (b) an asymmetric membrane.

Figure 2.16. Production scheme of a anodic aluminum oxide membrane (Smith 1973,1974).

Smith, A. W. 1973. Porous anodic aluminum oxide membrane. J. Electrochem. Soc. 120(8) 1068-69. 

Fumeaux, R. C., A. P. Davidson and M. D. Ball. 1987. Porous anodic aluminum oxide membrane catalyst support. European Patent Appl. 0,244,970A1. 

Xiong G, Elam JW, Feng H, Han CY, Wang HH, Iton LE, Curtiss LA, Pellin MJ, Rung M, Kung H, Starr PC (2005) Effect of atomic layer deposition coatings on the surface structure of anodic aluminum oxide membranes. J Phys Chem B 109 14059... 

Evans PR, Yi G, Schwarzacher W (2000) Current perpendicular to plane giant magnetoresistance of multilayered nanowires electrodeposited in anodic aluminum oxide membranes. Appl Phys Lett 76 481 83... 

Figure 7.3 AFM images of anodic aluminum oxide membrane (a), and Zn-Ni alloy nanorods (b, c) obtained using double templates (liquid crystal and AAO). (b) and (c) were obtained with different deposition charges, 0.6 C and 0.9 C, respectively. The scale of each picture is 1.6 x 1.6 p,m. (Reprinted from A. Foyet et al. J. Electroanal. Chem. 2007, 604, 137. Copyright (2007) Elsevier. With permission.)...

Gold nanowire arrays were also used by Andreu and coworkers for DNA detection [45]. Anodic aluminum oxide membranes were used as templates for galvanostatic Au electrodeposition followed by treatment in base to dissolve away the template leaving freestanding gold nanowires 330 nm in diameter and 2 fim in length. [Ru(NH3)6] + was used to measure charge before and after... 

For template-based parylene, anodized aluminum oxide membranes with 100 nm of pore diameters and a thickness of 60 xm are placed into a deposition chamber. Using surface characterization techniques, both approaches have been compared. 

One of the features of inorganic membranes is their controlled pore structure. Anodic aluminum oxide membranes have uniform cylindrical pores, and were applied to an investigation of the analysis of transport mechanism [ 12]. Another route involves the application of a micelle template to membrane preparation [44]. Cubic mesoporous silica (MCM48) membranes were prepared on a stainless steel supports [45] to possible applications for filtration membranes and membrane reactions. 

A novel one-sided NMR magnet has been developed for self-diffusion measurements in thin samples [7]. Using this technique, researchers have demonstrated measurements in bulk [BMIM][TFSI] and [BMIM][TFSI] confined in nanoporous anodized aluminum oxide membranes, as shown in Fig. 3. This operates at a proton Larmor frequency of 14.08 MFlz, and the expected appHcation is toward in situ measurements in portable energy devices. This method utilizes the fringe field to measure diffusion coefficients instead of conventional PFG-NMR. 

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