morphology and size control of mesoporous ... - hanyang
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Morphology and Size Control of Mesoporous ORMOSIL Particles
Prepared from Ternary Organosilane MixtureGyu Il Jung, Jung Soo Kim and Sang Man Koo*
Dept. of Chemical Engineering, Hanyang University, Seoul, 133-791, Korea
Introduction Organically Modified Silica (ORMOSIL)
particles as templates for mesoporous particlesNanostructured materials with tailored morphologies and sizes have
attracted intense interest in diverse field of nanotechnology due to their
novel properties, such as large surface area, controlled pores and
channels, permeability, and low density.
Facile, economic, and general, without using external templates,
methods have to be developed to synthesize tailored nanostructured
ORMOSIL particles, such as raspberry shaped, hollow, and rattle type
structures.
Preparation of ternary ORMOSIL particles
Variation in the morphology and size of mesoporous
particles depending on the relative ratio of
organosilanes in ternary ORMOSIL particles.
(P:PTMS, V:VTMS, A:APTMS)
ORMOSIL
particles
Solution
Acid ....... .... .. ..Base
Si
OR
RORO
Z
Si
OR
RORO
Y
Si
OR
RORO
X
SiOO
X
SiO
Y
SiO
O
X
SiO
OZ
SiOO
XSiOO
X
SiO
O
Y
Si OO
X
Si OO
Z
SiOO
X
SiO
OO
Y
SiOO
XSi
OO
X
Si
OO
Z
Emulsion droplets
from silane
mixtures
Co-condensation of
hydrolyzed silane
mixtures
BET N2 adsorption-desorption analysis analyses
of mesoporous nanostructured ORMOSIL particles
YX
Z
X
YZ
X
Y
Amine, Epoxy, Methacrylate, etc.
X and/or Y (major component)
Tailored mesoporous ORMOSIL particles, having various morphologies, such as raspberry shaped, hollow, and rattle type structures, were synthesized by a
selective dissolution of organosiloxane networks in ternary ORMOSIL particles prepared using a simple two-step process.
The first step, synthesis of monodisperse ORMOSIL particles with multi-layered structure, comprised a one-pot process in an aqueous solution using ternary
mixture from three organosilane monomers, 3-aminopropyl-trimethoxysilane (APTMS), vinyltrimethoxysilane (VTMS), and phenyltrimethoxysilane (PTMS).
In the second step, the ORMOSIL particles were treated with a mixture of water and alcohol with mild heating.
The size and morphology of mesoporous ORMOSIL particles could be easily adjusted by simply changing the relative ratios of PTMS, VTMS and APTMS in
reaction mixture for ORMOSIL particles.
These mesoporous ORMOSIL particles were converted to mesoporous silica particles, maintaining morphologies, simply by the heat treatment at 600 oC in air.
Z (minor components)
Phenyl, Vinyl, Mercapto,
Methyl, etc.
selective etching
by H2O/alcohol
Raspberry
shaped
Rattle type
Hollow
Experimental
Formation of mesoporous ORMOSIL particles
by selective dissolution
Conclusions
Multiple-functional
ORMOSIL particle
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Vo
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e A
dso
rbe
d c
m3
/g S
TP
Relative Pressure(P/P0)
pore distribution curve N2 adsorption-desorption curve
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Vo
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e A
dso
rbe
d c
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/g S
TP
Relative Pressure(P/P0)
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Pore Diameter(nm)
a
b
a
b
200nm
Rattle
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Vo
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/g S
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Relative Pressure(P/P0)
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/dlo
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Pore Diameter(nm)
a
b
a
b
100nm
Raspberry
a
b
a
b200nm
Hollow
200nm200nm200nm
After heat treatment at 600 ℃
Ratio of PTMS /
VTMS (ml)
P/V
(3.5/1.5)
P/V
(2.5/2.5)
P/V
(1.5/3.5)
P/V
(1/4)
P/V
(0.5/4.5)
A (0.5)Shape Sphere Sphere Rattle Raspberry Raspberry
Size (nm) 373 (±9) 347 (±9) 309 (±14) 301 (±19) 291 (±8)
A (1.5)Shape Hollow Rattle Rattle Rattle Raspberry
Size (nm) 198 (±9) 328 (±18) 222 (±18) 267 (±12) 223 (±19)
P/V
(3.5/1.5)
P/V
(2.5/2.5)
P/V
(1.5/3.5)
P/V
(1/4)
P/V
(0.5/4.5)
A
(0.5)
A
(1.5)