Adham Ahmed - uni of liverpool
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Transcript of Adham Ahmed - uni of liverpool
New drugs
medicinal chemistry of antimalarial and anticancer drugs.
'Dry Water' technology
potential for commercial applications in the storage and transportation of gases such as methane and carbon dioxide, as well as in green catalysis
Superficially porous silica
Uniform silica microspheres Formation of Organic Nanoparticles by Freeze-
Drying and Their Controlled Release Freeze-Align and Heat-Fuse: Microwires and
Networks from Nanoparticle Suspensions Systematic tuning of pore morphologies and
pore volumes in macroporous materials by freezing
Porous silica spheres in macroporous structures and on nanofibres
Hierarchically porous silica monoliths with tuneable morphology, porosity, and mechanical stability
Surface pattern for cell-growth Novel aligned silica monolith A new superficially porous silica particles
4µm
300nm
15µm
H. Zhang, J. Lee, A. Ahmed, I. Hussain, A.Cooper, Angew. Chem. Int. Ed. 2008, 47
A. Ahmed, P. Myers, H. Zhang, Ind. Eng. Chem. Res. 2010, 49, 602
A. Ahmed, N. Grant, L. Qian, H. Zhang, Nanosci. Nanotechnol. Lett. 2009, 1, 185
40µm30µmA. Ahmed, P. Myers, H. Zhang, J. Chem. Mater. 2011, in press
L. Qian, A. Ahmed, H. Zhang, Chem. Mater. 2011, in press
Outline
How to make hierarchically porous silica beads using polyHIPEs
Controlling the growth of silica particles
Changing the particles size and physical properties
Silica spheres on other porous structures
3µm
2µm
Emulsion Templated Porous Polymers (PolyHIPEs)
Poly(High Internal Phase Emulsion)
HIPE: high droplet phase volume, >70%
Monomeric continuous phase
Barby & Haq, Eur. Pat. 0,060,138 (1982)
N. Cameron, Polymer, 2005, 46, 1439
PolyHIPE (polyacrylamide) Beads
Dropwise addition of HIPE to long column of hot oil (sedimentation polymerisation)
H. Zhang, A. Cooper, Chem. Mater. 2002, 14, 4017
Adsorption of Silica Colloids
Structure collapsed50µm
5µm
2µm
Embedded into the macropore walls
Silica colloids -Poly(acrylamide) composite
Silica Synthesis in PAM Beads
25µm
H. Zhang, A. Cooper, Chem. Mater. 2004, 16, 4245
5µm
50µm
Microscopic silica-gel coating
Silica gel -Poly(acrylamide) composite
Acidic conditions
Synthesis of Silica Colloids in PAM Beads
Base H3N:
24 hrs
24 hrs
SoakedModified Stöber synthesisSilica precursor with organic template CTAB and PVA
A. Ahmed, P. Myers, H. Zhang, Ind. Eng. Chem. Res. 2010, 49, 602
Silica growth
silica nanospheres
Silica microspheres
30µmVoid diameter 10 – 30 µm
Interconnecting (window)
Internal pore structure
External pore structure
A. Ahmed, P. Myers, H. Zhang, Phil. Trans. R. Soc. A 2010, 368, 4351
2µm
300µm 30µm
30µm1mm
2µm5µm
Template removal by calcination
0.0 0.2 0.4 0.6 0.8 1.0
0
50
100
150
200
250
Quan
tity
Adso
rbed
(cm
³/g S
TP)
Relative Pressure (p/p°)
0.01 0.1 1 10 1000.0
0.1
0.2
0.3
0.4
0.5
Incr
emen
tal I
ntr
usi
on (m
L/g
)
Pore Diameter (µm)0 1 2 3 4 5 6 7 8 9 10
0.0
5.0x105
1.0x106
1.5x106
2.0x106
2.5x106
3.0x106
Inte
nsity
Position [o2Theta] (Copper (Cu))
1 10 1000.0
0.5
dV/d
log(w
) Pore
Vol.
(cm
³/g-1)
Pore Width (nm)
d- spacing 7.1nm
13.9µm
10.7nm
1.9nm
Surface area = 220 m2/g
Increasing silica precursor concentration
o Doubling TEOS amount
o Increased mechanical stability
o Lower surface area 53.6 m2/g
o A large portion of nanoparticles (approx. 200 nm)
2µm
20µm
Thicker pore wall ~10nm
4µm
2µm30µm
50µm 2µm
0.01 0.1 1 10 1000.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
Incre
menta
l Intr
usio
n (m
L/g
)Pore Diameter (µm)
1 10 1000.0
0.1
0.2
0.3
0.4
0.5
dV
/dlo
g(w
) P
ore
Vol (
cm
³/g·A
)
Pore Width (nm)0.0 0.2 0.4 0.6 0.8 1.00
50
100
150
200
Quantity
Adsorb
ed (cm
³/g S
TP
)
Relative Pressure (p/p°)
17.2µm12.0nmSurface area = 116 m2/g
Without PVA and CTAB
Without CTAB
Control the silica spheres size
Surface area = 165 m2/g
0 2 4 6 8 10
0.0
5.0x105
1.0x106
1.5x106
2.0x106
2.5x106
3.0x106
3.5x106
4.0x106
Inte
nsi
ty
Position [o2Theta] (Copper (Cu))
2 4 6 8 10
0.0
2.0x102
4.0x102
6.0x102
8.0x102
1.0x103
0.0 0.2 0.4 0.6 0.8 1.0
50
100
150
200
250
300
Quan
tity
Adso
rbed
(cm
³/g S
TP
)
Relative Pressure (p/p°)
1 10 1000
1
2
dV
/dlo
g(w
) P
ore
Vo
l.
(cm
³/g)
Pore Width (nm)
20µm
0.01 0.1 1 10 1000.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
0.40
Incre
menta
l Intr
usio
n (m
L/g
)
Pore Diameter (µm)
10µm
d- spacing 7.1nm
11.3µm
1.9nm
Surface area = 729 m2/g
d- spacing 2.5nm
Tuning silica beads surface area and porosity
Silica-PAM composite beads as a template
H. Zhang, G. Hardy, M. Rosseinsky, A.Cooper, Adv. Mater. 2003, 15, 78
0.01 0.1 1 10 1000.0
0.2
0.4
0.6
0.8
Incr
emen
tal I
ntr
usi
on (m
L/g
)
Pore Diameter (µm)1 10 1000.0
0.1
0.2
0.3
dV
/dlo
g(w
) P
ore
Vol.
(cm
³/g·A
)
Pore Width (nm)
4µm100µm
Internal pore structure
50µm
external pore structure
2µm
3.9µm7.6nm
Surface area = 247 m2/g
Porous Structures by Freezing method
Frozen
LN
Polymer solution
Freeze-dried
nanofibers Microfibers Monolith
Polymer %wv
Microsheets
Sub-Micron chitosan structures
0.1% wv
1% wv
1µm
200µm
L. Qian, A. Ahmed, H. Zhang., J. Mater. Chem., 2009, 19, 5212
L. Qian, E. Willneff, H. Zhang, Chem. Commun. 2009, 3946
Silica Spheres on Sub-Micron chitosan structures
1mm
1µm5µm 1µm10µm
A. Ahmed, P. Myers, H. Zhang, Phil. Trans. R. Soc. A 2010, 368, 4351
Chitosan sheet-like structure as a template
Chitosan fibers structure as a template
2µm
2µm
1% wv
0.1% wv 0.05% wv
2µm
1µm
0.01 0.1 1 10 1000.0
0.1
0.2
Incre
menta
l In
trusio
n (m
L/g
)
Pore Diameter (µm)
1 10 1000.00
0.05
0.10
0.15
0.20
0.25
0.30
dV
/dlo
g(w
) P
ore
Vol (c
m³/g·A
)
Pore Width (nm)0.0 0.2 0.4 0.6 0.8 1.00
50
100
Quantity
Adsorb
ed (cm
³/g S
TP
)
Relative Pressure (p/p°)
0 2 4 6 8 100
2000
4000
6000
8000
Inte
nsity
Position [o2Theta] (Copper (Cu)]2.2nm
Surface area = 169 m2/g
d- spacing 4.85nm
60µm
3.5nm
Template removal by calcination
Fe–sodium carboxymethyl cellulose composite fibre
5µm 5µm
1µm
10 20 30 40 50 60 70 800
200
400
600
Inte
nsi
ty
Position [o2Theta] (Copper (Cu)]
Surface area = 291 m2/gSCMC fibres modified with iron trichloride
α-Fe2O3 fibres (haematite)
Fe2O3 – Silica composite
Calcined 600 oC
Silica synthesis
0.1% wv
Conclusions
Highly porous silica beads
Controlling the particles size, surface area and porosity
Silica spheres on sub-micron polymer and metal oxide structures
1mm
5µm
Acknowledgements
Supervisors Dr. Haifei Zhang Prof. Peter Myers
ThermoFisher Dr. Harald Ritchie (development director)
CMD Rob Clowes Elizabeth Willneff (Manchester University) Lei Qian (University of Singapore)
