Advanced

In situ synchrotron small-angle X-ray scattering/X-ray diffraction study of the formation of SBA-15 mesoporous silica

Flodström, Katarina LU ; Teixeira, C V; Amenitsch, H; Alfredsson, Viveka LU and Lindén, M (2004) In Langmuir 20(12). p.4885-4891
Abstract
The initial stages of the formation of SBA-15 have been studied by in situ SAXS/XRD using synchrotron radiation. Modeling of both the diffuse scattering and the X-ray diffraction patterns obtained at different stages of the reaction results in a detailed description of the different reaction steps. The first step in the formation is the liquid-liquid phase separation of spherical P123-silicate hybrid micelles after which nucleation and growth of the 2D hexagonal phase occurs. Two-dimensional electron density maps calculated on the basis of the intensities of the Bragg reflections suggest that changes in the degree of intermicellar condensation are responsible for the time-dependent observations. The silica source (alkoxysilanes) may be... (More)
The initial stages of the formation of SBA-15 have been studied by in situ SAXS/XRD using synchrotron radiation. Modeling of both the diffuse scattering and the X-ray diffraction patterns obtained at different stages of the reaction results in a detailed description of the different reaction steps. The first step in the formation is the liquid-liquid phase separation of spherical P123-silicate hybrid micelles after which nucleation and growth of the 2D hexagonal phase occurs. Two-dimensional electron density maps calculated on the basis of the intensities of the Bragg reflections suggest that changes in the degree of intermicellar condensation are responsible for the time-dependent observations. The silica source (alkoxysilanes) may be partially unhydrolyzed long after formation of the hexagonal structure, since the kinetics of the mesophase evolution is notably slower when TEOS is used as the silica precursor as compared to TMOS. The results obtained for SBA-15 are compared with other published data on the formation of SBA-15 and of the smaller pore MCM-41 materials. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Langmuir
volume
20
issue
12
pages
4885 - 4891
publisher
The American Chemical Society
external identifiers
  • pmid:15984246
  • wos:000221846000018
  • scopus:2942733706
ISSN
0743-7463
DOI
10.1021/la049637c
language
English
LU publication?
yes
id
31b438e2-4a20-4943-84bb-be09c7316d57 (old id 153841)
date added to LUP
2007-07-11 11:49:19
date last changed
2017-11-12 03:23:41
@article{31b438e2-4a20-4943-84bb-be09c7316d57,
  abstract     = {The initial stages of the formation of SBA-15 have been studied by in situ SAXS/XRD using synchrotron radiation. Modeling of both the diffuse scattering and the X-ray diffraction patterns obtained at different stages of the reaction results in a detailed description of the different reaction steps. The first step in the formation is the liquid-liquid phase separation of spherical P123-silicate hybrid micelles after which nucleation and growth of the 2D hexagonal phase occurs. Two-dimensional electron density maps calculated on the basis of the intensities of the Bragg reflections suggest that changes in the degree of intermicellar condensation are responsible for the time-dependent observations. The silica source (alkoxysilanes) may be partially unhydrolyzed long after formation of the hexagonal structure, since the kinetics of the mesophase evolution is notably slower when TEOS is used as the silica precursor as compared to TMOS. The results obtained for SBA-15 are compared with other published data on the formation of SBA-15 and of the smaller pore MCM-41 materials.},
  author       = {Flodström, Katarina and Teixeira, C V and Amenitsch, H and Alfredsson, Viveka and Lindén, M},
  issn         = {0743-7463},
  language     = {eng},
  number       = {12},
  pages        = {4885--4891},
  publisher    = {The American Chemical Society},
  series       = {Langmuir},
  title        = {In situ synchrotron small-angle X-ray scattering/X-ray diffraction study of the formation of SBA-15 mesoporous silica},
  url          = {http://dx.doi.org/10.1021/la049637c},
  volume       = {20},
  year         = {2004},
}