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Formation of mesoporous SBA-15 from a colloidal perspective

Linton, Peter LU (2009)
Abstract
The formation of the hexagonal ordered mesoporous SBA-15 material has been invetsigated. The evolution from free spherical micelles into an ordered material was studied with time-resolved in-situ SAXS, USAXS and SANS measurements. Both the mesoscopic region and the colloidal region were monitored. Temperature, precursor and salt additions have been varied. From the time-resolved measurements the events taking place in the formation of SBA-15 was identified and put on a time line. An additional step was found in the formation of plate-like particles, 7 smaller primary particles build up a larger secondary particle. The aggregation of primary particles was highly specific, an oriented aggregation. It was possible to hinder the oriented... (More)
The formation of the hexagonal ordered mesoporous SBA-15 material has been invetsigated. The evolution from free spherical micelles into an ordered material was studied with time-resolved in-situ SAXS, USAXS and SANS measurements. Both the mesoscopic region and the colloidal region were monitored. Temperature, precursor and salt additions have been varied. From the time-resolved measurements the events taking place in the formation of SBA-15 was identified and put on a time line. An additional step was found in the formation of plate-like particles, 7 smaller primary particles build up a larger secondary particle. The aggregation of primary particles was highly specific, an oriented aggregation. It was possible to hinder the oriented aggregation by diluting the synthesis reaction at a specific time. Moreover, a salt addition at this specific time give rise to particles with a very large diameter while the thickness was constant. A model to explain the morphology of the mesoporous particles was proposed. The model is based on colloid and surface chemistry arguments and stresses the importance of the surface free energy of the respective interfaces. (Less)
Please use this url to cite or link to this publication:
author
supervisor
opponent
  • Prof. Goldfarb, Daniella, Weizmann institute of science, Rehovot, Israel
organization
publishing date
type
Thesis
publication status
published
subject
publisher
Physical Chemistry 1, Lund University
defense location
Sal B, chemical centre
defense date
2009-11-20 13:15
ISBN
978-91-7422-235-7
language
English
LU publication?
yes
id
6b0a11b6-2906-4c33-b792-f84a99d155d9 (old id 1496535)
date added to LUP
2009-10-27 16:20:11
date last changed
2016-09-19 08:45:11
@misc{6b0a11b6-2906-4c33-b792-f84a99d155d9,
  abstract     = {The formation of the hexagonal ordered mesoporous SBA-15 material has been invetsigated. The evolution from free spherical micelles into an ordered material was studied with time-resolved in-situ SAXS, USAXS and SANS measurements. Both the mesoscopic region and the colloidal region were monitored. Temperature, precursor and salt additions have been varied. From the time-resolved measurements the events taking place in the formation of SBA-15 was identified and put on a time line. An additional step was found in the formation of plate-like particles, 7 smaller primary particles build up a larger secondary particle. The aggregation of primary particles was highly specific, an oriented aggregation. It was possible to hinder the oriented aggregation by diluting the synthesis reaction at a specific time. Moreover, a salt addition at this specific time give rise to particles with a very large diameter while the thickness was constant. A model to explain the morphology of the mesoporous particles was proposed. The model is based on colloid and surface chemistry arguments and stresses the importance of the surface free energy of the respective interfaces.},
  author       = {Linton, Peter},
  isbn         = {978-91-7422-235-7},
  language     = {eng},
  publisher    = {ARRAY(0x7521d38)},
  title        = {Formation of mesoporous SBA-15 from a colloidal perspective},
  year         = {2009},
}