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Abstract:
The
organization
of
cationic
or anionic
organic
and
inorganic molecular species
to
produce
three-dimensional periodic biphase
arrays
is
described.
The
approach
uses cooperative nucleation
of
molecular inorganic
solution
species
with
surfactant
molecules
and
their
assembly
at
low
temperatures
into
liquid-crystal-like arrays.
The
organic/inorganic interface chemistry
makes
use
of
four synthesis routes with
(S+I-),
(S-I+),
(S+X-I+),
and
(S-M+I-)
direct
and
mediated
combinations
of
surfactant
(cationic
S+,
anionic
S-)
and
soluble inorganic
(cationic
I+,
anionic
I-)
molecular species.
The
concepts can be
widely
applied
to
generate
inorganic oxide,
phosphate
or
sulfide
framework
compositions.
Distinct
lamellar,
cubic silica mesophases were
synthesized
in
a
concentrated
acidic
medium
(S+X-I+),
with
the
hexagonal
and
the
cubic
phases
showing
good
thermal
stability. For
the
hexagonal
mesostructured
silica
materials high
BET
surface
areas
(>1000
m2/g)
are
found.
Hexagonal
tungsten(V1)
oxide
materials
were
prepared
in
the
presence
of
quaternary
ammonium surfactants in
the
pH
range
4-8.
Cubic
(Ia3d)
and
hexagonal
antimony(V)
oxides were
obtained
by acidifying
(pH
=
6-7)
homogeneous
solutions
of
soluble
Sb(V) anions
and
quaternary
ammonium
surfactants
at
room
temperature
(S+I-).
Using
anionic
surfactants,
hexagonal
and
lamellar lead
oxide
mesostructures
were
found
(S-I+).
Crystalline
zinc
phosphate
lamellar phases
were
obtained
at
low
synthesis
temperatures
(4°C)
and
lamellar
sulfide phases
could be also readily
generated
at
room
temperature.
The
synthesis procedure
presented
is
relevant
to the
coorganization
of
organic
and
inorganic
phases
in biomineralization
processes,
and
some
of
the
biomimetic
implications
are
discussed.
