Mesostructured Silica Fibers: Ring Structures in Reciprocal Space

Marlow, Frank; Leike, Ines; Weidenthaler, Claudia; Lehmann, Christian W.; Wilczok, Ursula

doi:10.1002/1521-4095(200103)13:5<307::aid-adma307>3.0.co;2-p

Cited by 34 publications

(40 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The tubes or fibers were found to have a 2D‐hexagonal mesostructure with circular orientation. Similar (free standing) unusual mesophase structures are known from CTAB‐templated fibers prepared by solvothermal methods and were named “circulites” or circular crystals 91, 92…”

Section: Synthesis Of Inorganic Mesostructured Materials Within Thmentioning

confidence: 81%

Mesoporous Structures Confined in Anodic Alumina Membranes

2011

View full text Add to dashboard Cite

The synthesis of nanoporous membranes based on different concepts and materials is a field of active research. This review focuses on the synthesis strategies, mesophase evolution mechanisms and potential applications of mesoporous materials confined within anodic alumina membranes (AAM). Following a rapid evolution of synthetic techniques, a significant number of different mesoporous materials (e.g., silica, titania, and carbon) with highly regular structures can now be prepared within these membranes. In recent years, efforts have also been made to understand the formation mechanisms of these hierarchical mesophases. The resulting organized nanoporous membranes open up a wide range of potential applications in fields such as templating oriented nanowires and controlled separation and release of molecules. For example, while various synthesis strategies can be used for the preparation of membrane-embedded nanowires, the latter can also be obtained as isolated objects after dissolution of the alumina host matrix. The review also discusses issues such as control of structural defects or integrity of interfaces that should be addressed in future research in order to fully exploit the potential of these hierarchical mesoporous channel structures.

show abstract

Section: Synthesis Of Inorganic Mesostructured Materials Within Thmentioning

confidence: 81%

Mesoporous Structures Confined in Anodic Alumina Membranes

2011

View full text Add to dashboard Cite

show abstract

“…In another case, a circular orientation of the mesostructure was observed. Similar (free‐standing) unusual mesophase structures are known to exist in cetyltrimethylammonium bromide (CTAB)‐templated materials prepared by solvothermal methods and have been named “circulites” or circular crystals 8. 9…”

Section: Summary Of Saxs Data Of Ctab‐templated Mesoporous Channel Symentioning

confidence: 93%

“…See text and Experimental Section for details. For the circular structure, a system of rings is found in reciprocal space 8. Indexation is given as for the normal hexagonal lattice.…”

Section: Summary Of Saxs Data Of Ctab‐templated Mesoporous Channel Symentioning

confidence: 99%

Tuning the Structure and Orientation of Hexagonally Ordered Mesoporous Channels in Anodic Alumina Membrane Hosts: A 2D Small‐Angle X‐ray Scattering Study

2006

View full text Add to dashboard Cite

Periodic mesoporous materials have attracted considerable attention during the last decade because of their promising applications as catalyst supports and nanoreactors, or as hosts for nanostructured materials with appealing optoelectronic properties. [1,2] Many of these applications will benefit from arrangements of preferentially aligned, ordered arrays of certain mesostructures. The evaporation-induced self-assembly (EISA) method has been established as an efficient process for the preparation of thin films with mono-oriented mesostructured domains. [3,4] However, the most frequently obtained films display hexagonally ordered channels that are aligned parallel to the surface of the substrate. [5] Recently, the synthesis of mesoporous materials within the regular, larger channels of anodic alumina membranes (AAMs) has been explored, with the aim of attaining greater control over the morphology of the mesoporous system.[6] A first approach, through a sol-gel synthesis route using the triblock copolymer poly(ethylene oxide) 100 -b-poly(propylene oxide) 65 -b-poly(ethylene oxide) 100 (PEO 100 PPO 65 PEO 100 or Pluronic F-127) as a structure-directing agent, resulted in 2D hexagonal mesostructures with two different orientations that were found to coexist at different ratios depending on the concentration of the surfactant. [7] In one case, the long axes of the mesopores were aligned with the long axes of the AAM channels (columnar orientation). In another case, a circular orientation of the mesostructure was observed. Similar (freestanding) unusual mesophase structures are known to exist in cetyltrimethylammonium bromide (CTAB)-templated materials prepared by solvothermal methods and have been named "circulites" or circular crystals. [8,9] The efficient EISA method can also be used to prepare AAM mesoporous composite materials by applying coating solutions that are typically used for the deposition of mesoporous silica films. When using cationic CTAB as a template, partially ordered mesoporous materials with aligned, columnar mesopores only in the vicinity of the alumina walls were obtained that showed promising behavior as molecular separators.[10] Use of the triblock copolymer PEO 20 PPO 70 PEO 20 (Pluronic123 or P123) as a template resulted in striking mesostructures with concentric or helical mesopores and single chains of spherical mesopores, depending on the confinement conditions imposed by alumina nanochannels with diameters of less than 100 nm. [11] In contrast, columnar mesopores were reported when the same template (P123) was used in the sol-gel approach in larger Anopore channels.[12] However, when a slightly different protocol at the same surfactant/silica ratio was used in the solgel synthesis route, hexagonal mesophases with mixed orientations resulted.[13] The presence of water vapor in the ageing process was investigated in a related study using the P123 template. [14,15] In this case, the circular orientation was favored over the columnar one at higher water pressure; this selectivity was attrib...

show abstract

“…Recently efforts were made to obtain these materials with controllable morphologies by regulating the synthesis conditions and by changing the inorganic precursors. Thus mesoporous thin fi lms (Meng et al , 2005;Dong et al , 2007;Zhao et al , 2007), tubes (Davis et al , 1997), spheres (Schacht et al , 1996;Lu et al , 1999;Trewyn et al , 2007), fi bers (Huo et al , 1997;Marlow et al , 2001;Wang et al , 2003aWang et al , , 2005Lu et al , 2004;Wu et al , 2004), etc., have been prepared. However, electrospinning has been the most simple and versatile method to fabricate continuous fi bers in micro/nanoscale.…”

Section: Optoelectronic Devicesmentioning

confidence: 99%

Functional nanofibers in microelectronics applications

Natarajan

2012

Functional Nanofibers and Their Applications

View full text Add to dashboard Cite

Mesostructured Silica Fibers: Ring Structures in Reciprocal Space

Cited by 34 publications

References 9 publications

Mesoporous Structures Confined in Anodic Alumina Membranes

Mesoporous Structures Confined in Anodic Alumina Membranes

Tuning the Structure and Orientation of Hexagonally Ordered Mesoporous Channels in Anodic Alumina Membrane Hosts: A 2D Small‐Angle X‐ray Scattering Study

Functional nanofibers in microelectronics applications

Contact Info

Product

Resources

About