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Structural characterization of micellar aggregates in sodium dodecyl sulfate/aluminum nitrate/urea/water system in the synthesis of mesoporous alumina

Caragheorgheopol, A; Caldararu, H; Vasilescu, M; Khan, Ali LU ; Angelescu, Daniel LU ; Zilkova, N and Cejka, J (2004) In The Journal of Physical Chemistry Part B 108(23). p.7735-7743
Abstract
The mechanism of templated synthesis of ordered mesoporous alumina according to the recipe proposed by Yada et al. (Yada, M.; Machida, M.; Kijima, T. Chem. Commun. 1996, 769) using sodium dodecyl sulfate (SDS) as template, has been investigated by NMR self-diffusion and spin and fluorescence probe techniques. In the precursor solutions urea was found to produce a substantial shortening of the long entangled cylindrical aggregates characteristic of the SDS micellar solutions with aluminum salt in large excess. The formation of mesostructured hexagonal alumina was followed using spin probes incorporated in the SDS aggregates. No structural changes were observed during urea hydrolysis, before the onset of the precipitation. In the... (More)
The mechanism of templated synthesis of ordered mesoporous alumina according to the recipe proposed by Yada et al. (Yada, M.; Machida, M.; Kijima, T. Chem. Commun. 1996, 769) using sodium dodecyl sulfate (SDS) as template, has been investigated by NMR self-diffusion and spin and fluorescence probe techniques. In the precursor solutions urea was found to produce a substantial shortening of the long entangled cylindrical aggregates characteristic of the SDS micellar solutions with aluminum salt in large excess. The formation of mesostructured hexagonal alumina was followed using spin probes incorporated in the SDS aggregates. No structural changes were observed during urea hydrolysis, before the onset of the precipitation. In the precipitate, the presence of the surfactant template is demonstrated as well as its interaction with the aluminum species. Time evolution of this interaction is also observed. Finally, the influence of the composition of the precursor system on the structure and thermal stability of as-synthesized alumina has been studied. It appears that hexagonally structured alumina is formed over a large range of compositions of the starting solution, with the dimension of the unit cell being almost constant. A model of precipitation is proposed that is based on the analogy with the formation of the hexagonal crystalline Al-DS precipitate in the ternary SDS/Al(NO3)(3)/water system. (Less)
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publishing date
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Contribution to journal
publication status
published
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in
The Journal of Physical Chemistry Part B
volume
108
issue
23
pages
7735 - 7743
publisher
The American Chemical Society
external identifiers
  • wos:000221833400031
  • scopus:3042594261
ISSN
1520-5207
DOI
10.1021/jp049482h
language
English
LU publication?
yes
id
f46db787-81c5-4c3f-afa5-472021821dcd (old id 153985)
date added to LUP
2007-07-11 08:29:19
date last changed
2017-01-01 06:38:44
@article{f46db787-81c5-4c3f-afa5-472021821dcd,
  abstract     = {The mechanism of templated synthesis of ordered mesoporous alumina according to the recipe proposed by Yada et al. (Yada, M.; Machida, M.; Kijima, T. Chem. Commun. 1996, 769) using sodium dodecyl sulfate (SDS) as template, has been investigated by NMR self-diffusion and spin and fluorescence probe techniques. In the precursor solutions urea was found to produce a substantial shortening of the long entangled cylindrical aggregates characteristic of the SDS micellar solutions with aluminum salt in large excess. The formation of mesostructured hexagonal alumina was followed using spin probes incorporated in the SDS aggregates. No structural changes were observed during urea hydrolysis, before the onset of the precipitation. In the precipitate, the presence of the surfactant template is demonstrated as well as its interaction with the aluminum species. Time evolution of this interaction is also observed. Finally, the influence of the composition of the precursor system on the structure and thermal stability of as-synthesized alumina has been studied. It appears that hexagonally structured alumina is formed over a large range of compositions of the starting solution, with the dimension of the unit cell being almost constant. A model of precipitation is proposed that is based on the analogy with the formation of the hexagonal crystalline Al-DS precipitate in the ternary SDS/Al(NO3)(3)/water system.},
  author       = {Caragheorgheopol, A and Caldararu, H and Vasilescu, M and Khan, Ali and Angelescu, Daniel and Zilkova, N and Cejka, J},
  issn         = {1520-5207},
  language     = {eng},
  number       = {23},
  pages        = {7735--7743},
  publisher    = {The American Chemical Society},
  series       = {The Journal of Physical Chemistry Part B},
  title        = {Structural characterization of micellar aggregates in sodium dodecyl sulfate/aluminum nitrate/urea/water system in the synthesis of mesoporous alumina},
  url          = {http://dx.doi.org/10.1021/jp049482h},
  volume       = {108},
  year         = {2004},
}