Morphological Design of Mesoporous Hybrid Materials - Mesoporous Organic-Inorganic Non-Siliceous Hybrid Materials - page 62

phosphonate-based mesophases and water/alcohol domains, leading to the creation
of sporadic huge macrovoids in hierarchical porous network.
The aerosol-assisted methodology is an effective approach to obtain spherical
particles of silica-based and non-silica-based materials, which is based on the
sprayed aerosol particles sacrificing and serving as “spherical templates” during
the heat treatment process [ 7 , 8 ]. Spherical aluminum phosphonate particles with
uniform mesopores could be fabricated with the assistance of triblock copolymers
by temperature-dependent spray-drying (Fig. 4.2 a, b) [ 9 , 10 ]. Pore diameter was
widely controlled from 6 to 21 nm by changing surfactants and adding organic
additives. In order to obtain periodic mesostructures inside the spherical morphol-
ogy, the evaporation rate of the solvents (ethanol and water) should be moderate.
This could allow the residual soluble species to infiltrate the surfactant scaffolds
for the construction of resultant hybrid frameworks with sufficient density [ 9 ].
With a further increase in the amount of surfactant molecules with expanded cores
(PS- b -PEO), aluminum phosphonates of a fibrous morphology (Fig. 4.2 c, d) were
Fig. 4.2 Porous spherical ( a , b ) and fibrous ( c , d ) aluminum phosphonate particles prepared
through a spray-drying method in the presence of P123 and colloidal PS- b -PEO templates,
respectively. a , b Reproduced from Ref. [ 9 ] by permission of The Wiley-VCH. c , d Reproduced
from Ref. [ 10 ] by permission of The American Chemical Society