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E(z) /kT. Nanoparticle Assembly. Oil phase. Water. A. OH . H 2 O interior. H 2 O. OH . HO . Oil. E min. 20 µ m. Toluene/CdSe. z/R. C. 80 m m. 20 m m. 100 nm. TCB. 50 nm. Water. - PowerPoint PPT Presentation
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NIRT: Controlling Interfacial Activity of Nanoparticles: Robust Routes to Nanoparticle-based Capsules, Membranes, and Electronic Materials (CBET 0609107)
Todd Emrick and Thomas P Russell, Polymer Science & Engineering Department, University of Massachusetts AmherstAnthony Dinsmore and Narayanan Menon, Physics Department, University of Massachusetts Amherst
Benny D. Freeman, Chemical Engineering Department, University of Texas at Austin
Objectives: Harness the interfacial activity of nanoparticles, and the reactivity of functionalized ligands,for the preparation of robust, self-assembled structures , devices, and membranes
Materials for nano-composite films
Responsive Nanocomposites: using ligands to direct nanoparticles to polymer domains and interfacial boundaries
Thermalannealing
Idealized schematic of responsive nanocomposite
Effect on mechanical properties??
50 nm 100 nm
25% OH terminated:NPs segregate to PS-PVP interface
50% OH terminated:NPs distributed within PVP domain
OH
OH HO
Lamellar morphology (solvent annealed films) with avg. 2.4 nm Au NPs avg. 4.5 nm diameter Au NPs
Nanoparticle ripening + entropic penalty =
reorganization
170 deg C
Diblock copolymer host: polystyrene-poly(4-vinylpyridine)
Self-assembled nanorods and bionanorods using fluid interfaces
Hydrophilic segment Hydrophobic segment
* S
O
O
O O S O O *
100-X
O
O
SO
O O-Y+
S+Y-O
O
OX
Hydrophilic segment Hydrophobic segment
* S
O
O
O O S O O *
100-X
O
O
SO
O O-Y+
S+Y-O
O
OX
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
0.5
5
10
15
20
25
30
0 5 10 15 20 25 30
Wat
er P
erm
eabi
lity
(L.u
m/(m
2 .h.b
ar))
pH
t (days)
BPS-35N BPS-32K
BPS-32K/0.5%Au
94
95
96
97
98
99
100
5
10
15
20
25
30
0 5 10 15 20 25 30
Salt
Rej
ectio
n (%
)
pH
t (days)
BPS-35N
BPS-32KBPS-32K/0.5%Au
PFDPFD
Low Concentration
PFDPFD
PFD
High Concentration
PFD
PFDPFD
High Concentration
PFDPFD
Washing
H2Ointerior
Oilphase
NanoparticleAssembly
20µm
Fluorescence confocal imagesof quantum dots on water droplets in a continuous oil phase
TOPO-covered CdSe quantum dots
122
/
/
/
/
/
/
/
/2
/2
WO
WP
WO
OP
WO
WP
WO
OPWO R
zRzRzE
RzEWO
OPWP
/
//at min
z/R
E(z)/kT
Oil
Water
Emin
Pieranski, P. Phys. Rev. Lett 45, 569 (1980)
WP /
OP /
WO /
Interfacial assembly of nanoparticles: droplets and sheets
TCB
Water
20 mm80 mm
Droplet resizingthrough track-etch
membranes Confocal images
reduction in droplet size from
200 mm to 10 mm and less
Lin, Y., Skaff, H., Emrick, T., Dinsmore, A. D. & Russell, T. P., Science 299, 226-229.
2////
2
min/ lEngery Wel lInterfacia OPWPWOWO
OPREEE
Interfacial energy well:
The structure and orientation of nanorods at the liquid-liquid interface can be manipulated by varying nanorod concentration in the bulk. At low TMV concentration, the rods orient parallel to the interface, which maximizes interfacial stabilizaiton. At high TMV concentrations, the rods orient normal to the interface, both mediating the interfacial interactions and neutralizing inter-rod electrostatic repulsion.
For charged nanorods like TMV, repulsive forces dominate the oil-water interfaces, which is strongly affected by the ionic strength, but not the pH, of the bulk solution in the range of pH = 6~8. Removal of the buffer solution leads to cleavage of the TMV nanorods at the oil/water interface.
25 µm
400 nm0.2 mg/ml
25 µm
400 nm0.2 mg/ml
B
0.8 mg/ml
B
0.8 mg/ml
5 µm
400 nm
B
0.8 mg/ml
B
0.8 mg/ml
5 µm
400 nm
B
0.8 mg/ml
B
0.8 mg/ml
5 µm
400 nm
Low concentration High concentration
/ / / / /2 sin 2 ( )o w p w p oE RL RL
Where / /
/
cos p w p o
o w
L>>R
2/ / / / /( ) ( )2p w o w p o p w p oE R Rh
Oil
Oil
Oil
Oil
Oil
Oil
1. Concentration2. pH value3. Ionic strength4. In-plane compression
Conditions
Au nanoparticles: EG4-058ACitrate-stabilized gold nanoparticles in water
~20 nm in diameter~1 mg/ml in water
Di-sulfonated poly(arylene ether sulfone) (BPS):BPS-XY series, X = mol% of disulfonated monomer (0<X<100), Y = “H” (free acid form) , “N” (sodium salt form), or “K” (potassium salt form).
Acid/base tolerance: steady water permeability and salt rejection over a wide range of pH
1. Measured in cross-flow cells. Feed solution: 2000 ppm NaCl, pressure = 27.2 atm (400 psig), flow rate = 1 gpm, temperature = 25oC.
2. BPS-32K/0.5%Au: BPS-32K with 0.5 wt% of Au nanoparticles (EG4-058A)
Film Formation at the Interface
0 50 100 150 200 25020
25
30
35 0.4 mg/mL 0.25 mg/mL 0.025 mg/mL
IFT
[mN
/m]
Time [min]
B
C
A
H2O
Toluene/CdSe
D
1 mm
4.6 nm CdSe in Toluene/Water
H. Z
ettl,
Uni
vers
ität B
ayre
uth