Magnetically induced orientation of mesochannels inside porous anodic alumina membranes under ultra high magnetic field of 30 T: Confirmation by TEM

Mesoporous materials prepared through the self-assembly of surfactants have attracted wide attention because of their many potential applications. The mesostructural, compositional, and morphological controls of mesoporous materials have been extensively studied thus far. In particular, the macroscopic alignments of one-dimensional (1D) mesochannels and their controls are quite important for the creation of advanced functional materials. In most cases, the direction of mesochannels in mesoporous films lies parallel to the substrate. Vertical orientation of the mesochannels can realize high diffusion and accessibility of guest species from the outside. Here, I review the recent progress on this emerging research field. Various methods have been proposed for the preparation of vertically oriented mesoporous thin films using high magnetic field, shear flow, modification of the substrate, and other methods. I also briefly introduce their applications and a perspective for the future.©2013 The Ceramic Society of Japan. All rights reserved.Key-words : Mesoporous material, Surfactant, Thin film, High magnetic processing [Received April 25, 2013; Accepted June 23, 2013] 1. Mesoporous materials by self-assembly of surfactants Ordered mesoporous materials prepared through 'self-assembly of surfactants' have attracted growing interest due to their special properties, including uniform mesopores (250 nm) and high specific surface areas. 1),2) According to the International Union of Pure and Applied Chemistry (IUPAC), porous materials are classified according to their pore sizes: microporous materials with pore sizes below 2 nm, mesoporous materials with pore sizes between 2 and 50 nm, and macroporous materials with pore sizes exceeding 50 nm.3),4) Zeolites are traditional microporous materials that have been utilized for practical applications in catalysts and adsorbents. Although the microporous materials have high surface areas, due to their small-sized pores, their applications are limited to reactions only for relatively small molecules. Recently, metalorganic frameworks (MOFs) or porous coordination polymers (PCPs) consisting of metal ions coordinated with organic molecules have been extensively studied and used for the storage of gases such as hydrogen and carbon dioxide. 5),6) However, their pore size is still small. In contrast, several types of macroporous materials, such as inverse opal films, track-etched polycarbonate membranes, and porous anodic alumina membranes, have been reported thus far. However, such pore expansion seriously decreases surface area.Unlike other porous materials, mesoporous materials can be easily prepared under a wide range of synthetic conditions. Mesoporous materials exhibit several defined mesostructures, such as lamellar, two-dimensional (2D) hexagonal, three-dimensional (3D) hexagonal, and bicontinuous cubic mesostructures. Furthermore, many framework compositions (e.g., silica, organosilica, metal, and non-siliceous oxides) and various morphologies (e.g., nanoparticle, monolith, a...

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“…68) In general, the mesochannels prepared from P123 block copolymer were circularly packed like stacked donuts [ Fig. 7(a)].…”

Section: Use Of Confined Space 41 Cylindrically Confined Spacementioning

confidence: 99%

Field-Induced alignment controls of one-dimensional mesochannels in mesoporous materials

Yamauchi

2013

J. Ceram. Soc. Japan

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147

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“…Titania rods were also fabricated as shown in Figure 2(b), revealing that our procedure is applicable beyond silica. The densities of the rods were lower rather than that of the silica tubes/rods prepared by PAA membranes [2,[7][8][9][10], because the number of the pores in the PC membranes is relatively lower (Figure 3). Also, the fabricated rods were randomly placed and inclined to the substrate (Figure 2), because the pores in the PC membranes are randomly dispersed and the pores are not oriented completely perpendicular, but are tilted to the substrate (Figure 3).…”

Section: Resultsmentioning

confidence: 95%

Fabrication of Mesostructured Silica and Titania Rods on Substrates by Using Polycarbonate Membranes

Suzuki

Yamauchi

2010

Journal of Nanomaterials

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By using the polycarbonate membrane a template, mesoporous silica rods are fabricated on a silicon substrate in one pot. From scanning electron microscope (SEM) images, the creation of fibrous morphology is confirmed over the entire area. The diameter of the obtained rods is consistent with that of the template. Transmission electron microscope (TEM) images revealed that the tubular mesochannels are uniaxially oriented parallel to the longitudinal axis of the silica rods. The mesoporous titania rods with anatase crystalline frameworks are also fabricated.

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“…We have fabricated many kinds of oriented ceramics by the slip casting in a high magnetic field followed by sintering, such as Al2O3, TiO2, ZnO, AlN, SiC, Si3N4, etc., 52 -64) their composites, 60,65) and multi-component ceramics by reaction sintering 66) . However, when we use whisker or plate-like particles, special attention is necessary due to the effect of gravity energy 67,68) that is the highest energy in the colloidal dispersion system 69) .…”

Section: Textured Ceramicsmentioning

confidence: 99%

Forming and Microstructure Control of Ceramics by Electrophoretic Deposition (EPD)

Sakka

Uchikoshi

2010

KONA

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Magnetically induced orientation of mesochannels inside porous anodic alumina membranes under ultra high magnetic field of 30 T: Confirmation by TEM

Cited by 12 publications

References 41 publications

Field-Induced alignment controls of one-dimensional mesochannels in mesoporous materials

Field-Induced alignment controls of one-dimensional mesochannels in mesoporous materials

Fabrication of Mesostructured Silica and Titania Rods on Substrates by Using Polycarbonate Membranes

Forming and Microstructure Control of Ceramics by Electrophoretic Deposition (EPD)

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