Control of morphology in synthesizing mesoporous silica
Chung-Yuan Mou* and Hong-Ping Lin
*Department of Chemistry, National Taiwan University,
Taipei, Taiwan 106
Abstract: Mesoporous silica can be synthesized by either the
alkaline route or the acidic route, both using surfactants as templates.
Morphological transformations of mesoporous silica can produce various
hierarchical orders. Different morphologies are produced under different
synthetic conditions. In the alkaline route, the surfactant/silicate
liquid crystal system undergoes phase transformation to form vesicles
and further transforms to the hexagonal phase. The results are tubule-within-tubule
and hollow pillar-within-sphere structures depending on cosurfactant/surfactant
composition. Using nitric acid in the acidic route, one can obtain hierarchical
ropes or gyroids depending on stirring conditions. Ammonia hydrothermal
treatment can induce further morphological transformation to nanotubes
of mesoporous silica.
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