The controlled synthesis of aluminum-based surfactant
mesophases by the homogeneous precipitation
method using urea and sodium dodecyl sulfate was
described by Yada et al. [17,18,37]. It was suggested
that dodecyl sulfate surfactant initially forms a layered
mesophase with an interlayer spacing depending
on the amount and type of surfactant. The surfactants
form a layer, which links the sheets of aluminum oxyhydroxide
species. As a result of further hydrolysis
of urea, the layered mesophase is transformed into a
hexagonal form through interlayer condensation and
cross-linking of the Al–OH groups in any adjacent
aluminate sheets [17]. The proper method of removing
dodecyl sulfate from the alumina mesophase seems to
be the crucial point in the preparation of mesoporous
alumina by this method. Thermal decomposition of
dodecyl sulfate from as-synthesized alumina, prepared
by Yada’s method, studied by sample-controlled thermal
analysis, was reported by Sicard et al. [38]. The
alkyl chain of the surfactant was completely removed
below 200 ◦C, while the sulfate groups were removed
at temperature between 400 and 550 ◦C. These results
indicate that there is a strong interaction between
the sulfate head groups and the alumina framework.
hexagonal form through interlayer condensation and
cross-linking of the Al–OH groups in any adjacent
aluminate sheets [17]. The proper method of removing
dodecyl sulfate from the alumina mesophase seems to
be the crucial point in the preparation of mesoporous
alumina by this method. Thermal decomposition of
dodecyl sulfate from as-synthesized alumina, prepared
by Yada’s method, studied by sample-controlled thermal
analysis, was reported by Sicard et al. [38]. The
alkyl chain of the surfactant was completely removed
below 200 ◦C, while the sulfate groups were removed
at temperature between 400 and 550 ◦C. These results
indicate that there is a strong interaction between
the sulfate head groups and the alumina framework.