APPLIED CHEMICALS AND MATERIALS DIVISION
Lauren F. Greenlee
Hope A. Weinstein, Michael Voecks, Katie Estoque, Nikki S. Rentz,
Nicholas M. Bedford
Iron Nanoparticle Synthesis and
Immobilization
200 nm
Advances in Materials and Processes for Polymeric
Membrane Mediated Water Purification
Pacific Grove, CA
February 18, 2015
APPLIED CHEMICALS AND MATERIALS DIVISION
Research Motivation & Direction
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APPLIED CHEMICALS AND MATERIALS DIVISION
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ENGINEERED NANOPARTICLE SYSTEMS
Research Motivation: Water & Energy
http://www.nrel.gov/http://www.chk.com/corporate-responsibility/ehs/environment/water/Pages/information.aspxhttp://voxglobal.com/2011/03/the-energy-water-nexus-an-emerging-risk/
NIST mission:To promote U.S. innovation and industrial competitiveness by advancing measurement science, standards, and technology in ways that enhance economic security and improve our quality of life.
FeNi nanoparticles
NP
APPLIED CHEMICALS AND MATERIALS DIVISION
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ENGINEERED NANOPARTICLE SYSTEMS
Current Project Applications
Water Treatment: Heavy metals, textile dyes
Ammonia Synthesis: Fertilizer, fuel
Fuel Electrooxidation: Fuel cells
Need: Reactive/catalytic materials that are more efficient, selective, durable, and low-cost
APPLIED CHEMICALS AND MATERIALS DIVISION
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ENGINEERED NANOPARTICLE SYSTEMS
Why Nanoparticles?
Core/shell size, composition, atom-
scale/electronic structure
Shell thickness
Particle size
Surface lattice
structure
Core lattice structure
Spatial arrangement of atoms at surface
FeNiO O
Nanoparticle Properties: Enhanced Performance
% Fe, % Ni, % O
Key Features:• Structural disorder• Multi-metal combinations• Oxide/hydroxide phases• Surface functionalization• Nanoscale morphology / structure• Many catalytic surface sites
APPLIED CHEMICALS AND MATERIALS DIVISION
ENGINEERED NANOPARTICLE SYSTEMSCharacterization-Enabled Nanoparticle Design
Synthesis Performance
Characterization
Need: Nanoparticles designed for specific catalytic/reactive systems.
RepeatabilityControlOptimization
What are we making?
RepeatabilityTesting optimization
Does it work?
Atom-level structureIn situ/in operandoMulti-technique approach
How/why does it work?
Goal: Structure-function relationships to guide design
critical component of cycle
NPs
APPLIED CHEMICALS AND MATERIALS DIVISION
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ENGINEERED NANOPARTICLE SYSTEMS
Measurement Techniques for Nanoparticle Characterization
Microscopy: TEM, SEM, t-SEM
Powder X-Ray Diffraction
30 40 50 60 70 80 90
Unstabilized
0.0005 CMC
0.05 ATMP
0.5 ATMP
Inte
nsity (
arb
itra
ry u
nits)
2-Theta (deg.)
0.8 ATMP
Dynamic light scattering: Size, Zeta Potential
0
500
1000
1500
2000
2500
3000
3500
4000
-80
-60
-40
-20
0
20
2 4 6 8 10 12
Avera
ge S
ize (
nm
)
Ze
ta P
ote
ntia
l (mV
)pH
Synchrotron X-ray Techniques: In situ/ex situ Measurements for Atom-Level Structure
PdAu 1:3 PdAu 1:1
PdAu 2:1
IR/Raman/UV-vis Spectroscopy
in situ, in operando
APPLIED CHEMICALS AND MATERIALS DIVISION
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ENGINEERED NANOPARTICLE SYSTEMS
Catalyst Development: Reduction/Replacement of Precious Metals
Optimization of:StructureMetal combinationsMorphology
Chun et al. (2010) ES&T 44, 5079-5085.Alayoglu and Eichhorn (2008) JACS 130, 17479–17486.Zhang et al. (2010) Nano Lett. 10, 638-644.
Fe Fe
2 3 4 5 6 7 8 9 10
-2.5
-2.0
-1.5
-1.0
-0.5
0.0
0.5
1.0
1.5
2.0
2.5
ATMP
HTPMP
DTPMP
Fe NPs
G(r
)
r (Å)
oxide
metal-metal
oxide
extended lattice structure, peak shifts suggest alloying/oxide
Our focus: Non-precious metal nanoparticles & ligand control of structure/morphology
HE-XRD
Fe-Pd Rh-Pt
APPLIED CHEMICALS AND MATERIALS DIVISION
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ENGINEERED NANOPARTICLE SYSTEMS
Aqueous Synthesis Method: Scalable & Adaptable
• Molar ratio of stabilizer:Fe• Fe concentration• Fe salt / oxidation state• Type of stabilizer
• Molar ratio of BH4:Fe• Rate of NaBH4 addition• Age of NaBH4
• Molar ratio of stabilizer:Ni• Molar ratio of Ni:Fe• Type of stabilizer• Rate of Ni/stabilizer
addition• Time between BH4 addition
and Ni/stabilizer addition
APPLIED CHEMICALS AND MATERIALS DIVISION
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ENGINEERED NANOPARTICLE SYSTEMS
Nanoparticle Immobilization
Goals:• Reactivity/performance enhancement• Control of location
100 nm
400 nm
10 mm
Fe NPs in PES pore wall
Carbon
FeNi NPs
APPLIED CHEMICALS AND MATERIALS DIVISION
Synthesis and Characterization of Iron-
Nanoparticle-Immobilized PES Membranes
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APPLIED CHEMICALS AND MATERIALS DIVISION
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ENGINEERED NANOPARTICLE SYSTEMS
Nanoparticle Immobilization in Filtration Membranes
Surface Deposition
Incorporation into Polymer Matrix
Pore Deposition
Flexibility in material design: Nanoparticle synthesis Nanoparticle location Membrane pore
structure and material
APPLIED CHEMICALS AND MATERIALS DIVISION
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ENGINEERED NANOPARTICLE SYSTEMS
Iron NP Oxidation & Contaminant Degradation
Fe
OH*, H2O2, O2*-, Fe(IV)
H2 gas
+ H2O & O2
Pesticides & Herbicides
Heavy Metals
Cr6+As3+
Pb2+
IndustrialChemicals
APPLIED CHEMICALS AND MATERIALS DIVISION
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ENGINEERED NANOPARTICLE SYSTEMS
Synthesized Fe NPs
200 nm
Iron Metal
Magnetite/Maghemite(Fe3O4/g-Fe2O3)
(ATMP)
APPLIED CHEMICALS AND MATERIALS DIVISION
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ENGINEERED NANOPARTICLE SYSTEMS
Casting Solution Preparation & Membrane Casting
Polyethersulfone (PES)
0 - 2.0 % synthesized iron nanoparticles
0 – 2.0 wt % pore former:•Polyvinylpyrrolidone (PVP)
Solvent
APPLIED CHEMICALS AND MATERIALS DIVISION
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ENGINEERED NANOPARTICLE SYSTEMS
Parameters and Values Tested
Stabilizer (mol
stabilizer/mol Fe) Amino tris(methylene phosphonic
acid) (ATMP) (0.05 or 0.3)
Solvent Type dimethyl sulfoxide (DMSO)
dimethylacetamide (DMAC)
dimethylformamide (DMF)
Concentration of
nanoparticles in
casting solution
(g/L)
0, 1, 5, 10, 20
APPLIED CHEMICALS AND MATERIALS DIVISION
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ENGINEERED NANOPARTICLE SYSTEMS
Effect of Nanoparticles on Membrane Performance
Taurozzi, J.S. et al. (2011) Desalination 269, 111-119.Choi, J.-H. et al. (2006) Journal of Membrane Science 284, 406-415.
Taurozzi (2011) – C60 nps (139 nm) in 12% PSf by wet phase inversion
Choi (2006) – Carbon nanotubes in 15% PSf by wet phase inversion
In general, addition of nps causes:• Increase in viscosity• Increase then decrease in flux• Decrease then increase in solute rejection
APPLIED CHEMICALS AND MATERIALS DIVISION
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ENGINEERED NANOPARTICLE SYSTEMS
Viscosity: Increase with Nanoparticle Concentration
0
0.1
0.2
0.3
0.4
0.5
0 0.5 1 1.5 2 2.5
Vis
co
sity (
Pa
*s)
Nanoparticle Concentration (wt%)
NMP
DMAc
DMSO
DMF
APPLIED CHEMICALS AND MATERIALS DIVISION
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ENGINEERED NANOPARTICLE SYSTEMS
Effect of Nanoparticles on Membrane Thickness and Flux
All experiments run at 1 bar
APPLIED CHEMICALS AND MATERIALS DIVISION
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ENGINEERED NANOPARTICLE SYSTEMS
Polymer-Solvent Miscibility & Membrane Pore Structure
Lau W.W.Y. et al. (1991) Journal of Membrane Science 59, 219-227.
Polymer precipitation curvesPES solubility: DMAC > DMF > DMSO
Polymer + Solvent + NPs
Non-solvent (H2O)
DMAC: slow outflux of solvent = fast influx of non-solvent = delayed demixing, macrovoid formation & larger polymer precipitates/aggregates form
DMSO: fast outflux of solvent = slow influx of non-solvent = reduction in macrovoid formation, smaller polymer precipitates, cellular or nodular structures form
Flux decreases with increasing PES-solvent solubility
APPLIED CHEMICALS AND MATERIALS DIVISION
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ENGINEERED NANOPARTICLE SYSTEMS
Cross-Section Morphology
13.8 wt % PES
b ca
d e f
20 mm
20 mm
20 mm
20 mm 20 mm20 mm
13.8 wt % PES, 1 wt % Fe NPs
DMAC DMF DMSO
DMAC DMF DMSO
APPLIED CHEMICALS AND MATERIALS DIVISION
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ENGINEERED NANOPARTICLE SYSTEMS
Surface Morphology
b ca
d e f
400 nm400 nm
200 nm200 nm
2 mm
4 mm
13.8 wt % PES, 1 wt % Fe NPs
DMAC DMF DMSO
13.8 wt % PES
DMAC DMF DMSO
APPLIED CHEMICALS AND MATERIALS DIVISION
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ENGINEERED NANOPARTICLE SYSTEMS
Nanoparticles: Casting Solution Additive
Non-Solvent (e.g., butanol, water) Polymer (e.g., polyvinylpyrrolidone)
Li, Z and Jiang C. (2001) Journal of Applied Polymer Science 82, 283–291.M.-J. Han, S.-I: Nam (2002) Journal of Membrane Science 202, 55-61.
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
0 0.2 0.4 0.6 0.8 1
Vis
cosi
ty (
Pa.s
)
Relative Content Value (-)
1-Butanol
Water
15 wt % PES/NMP
Non-Solvent:• Closer to solubility limit• Increase in viscosity• Decrease in flux• Moves to polymer-lean phase in phase
inversion
Polymer:• Suppression of macrovoids• Increase in viscosity• Increase then decrease in flux• Stays entangled with membrane
polymer in phase inversion
Thermodynamics:Enhanced demixingdue to lower stability (solubility)
Kinetics:Delayed demixingdue to rheology / diffusion
APPLIED CHEMICALS AND MATERIALS DIVISION
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ENGINEERED NANOPARTICLE SYSTEMS
Thermodynamics vs. Kinetics: Solvent Dependence
0
0.1
0.2
0.3
0.4
0.5
0 1 2 3
Vis
cosity (
Pa*s
)
Nanoparticle Concentration (wt%)
NMP
DMAc
DMSO
DMF
Thermodynamics dominating? Increase in flux with NP additionIncrease in viscosity with NP concentration
Kinetics dominating?Decrease in flux with NP concentrationIncrease in viscosity with NP concentration
APPLIED CHEMICALS AND MATERIALS DIVISION
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ENGINEERED NANOPARTICLE SYSTEMS
Nanoparticle-Polymer Interactions in Solution
• Polymer functional groups• Stabilizer/pore former• Nanoparticle concentration• Polymer concentration• Ex situ vs. in situ NP synthesis
Polymer conformation & dynamics changes due to NPs
APPLIED CHEMICALS AND MATERIALS DIVISION
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ENGINEERED NANOPARTICLE SYSTEMS
Nanoparticle Location During Phase Inversion
100 nm
500 nm
3 mm
APPLIED CHEMICALS AND MATERIALS DIVISION
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ENGINEERED NANOPARTICLE SYSTEMS
Iron Nanoparticle Oxidation in PS Membrane
Oxidation on a gold QCM crystal surface
Oxidation on pores of PES membrane
400 nm 400 nm
200 nm 200 nm
APPLIED CHEMICALS AND MATERIALS DIVISION
Controlling Fe Nanoparticle Oxidation
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APPLIED CHEMICALS AND MATERIALS DIVISION
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ENGINEERED NANOPARTICLE SYSTEMS
Bimetallic nanoparticles: Ni:Fe ratio
Greenlee, L.F. et al. (2012) Environmental Science & Technology 46, 12913.
0.5 mmol Ni:mol Fe 5 mmol Ni:mol Fe
100 mmol Ni:mol Fe 1000 mmol Ni:mol Fe
APPLIED CHEMICALS AND MATERIALS DIVISION
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ENGINEERED NANOPARTICLE SYSTEMS
Iron NP oxidation in water: Quartz crystal microbalance measurements
Greenlee, L.F. et al. (2012) Environmental Science & Technology 46, 12913.
APPLIED CHEMICALS AND MATERIALS DIVISION
Water Treatment with FeNi Nanoparticles
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APPLIED CHEMICALS AND MATERIALS DIVISION
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ENGINEERED NANOPARTICLE SYSTEMS
FeNi Nanoparticles: Orange G dye removal from water
Textile Industry: 2nd largest water contributor to water contamination• Dyes• Metals
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
0 20 40 60 80
Co
nce
ntr
atio
n (
g/L)
Time (min)
100 mg/L
75 mg/L
50 mg/L
25 mg/L
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
0 20 40 60 80
Co
nce
ntr
atio
n (
g/L)
Time (min)
100 mg/L
50 mg/L
1:1 Ni:Fe, core-shell 1:1 Ni:Fe, alloy
1 g/L
•CHED: Undergraduate Research Posters•Hall C - Colorado Convention Center
•12:00pm - 2:00pm Mon, Mar 23Environmental Chemistry
APPLIED CHEMICALS AND MATERIALS DIVISION
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ENGINEERED NANOPARTICLE SYSTEMS
Conclusions & Future Work
Future Work: Optimization of FeNi nanoparticles for dye removal• Characterization of NPs• FeNi immobilization in membranes
• NP concentration• Polymer type and concentration
• Membrane characterization• Flux• Viscosity• Neutron scattering / SAXS experiments / microscopy• Orange G dye removal
Conclusions:• Viscosity, flux, and microscopy data can be used to understand nanoparticles
as a membrane additive• Iron nanoparticle oxidation can be controlled through addition of a second
metal (e.g., nickel)• FeNi nanoparticle structure affects Orange G dye removal
APPLIED CHEMICALS AND MATERIALS DIVISION
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ENGINEERED NANOPARTICLE SYSTEMS
Thank You! Questions?
Contact Information:Lauren [email protected]
AcknowledgementsProf. Andrew Herring & lab members, Colorado School of MinesProf. Matthew Liberatore & lab members, Colorado School of MinesNIST TEM – Roy Geiss, Alex Curtin, Ann Debay, Taylor WoehlNIST XRD – Justin ShawCU TEM – Tom GiddingsNIST/Argonne HE-XRD: Nicholas Bedford
APPLIED CHEMICALS AND MATERIALS DIVISION
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ENGINEERED NANOPARTICLE SYSTEMS
APPLIED CHEMICALS AND MATERIALS DIVISION
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ENGINEERED NANOPARTICLE SYSTEMS
Stabilizers used during NP synthesis
Amino tri(methylene phosphonicacid) (ATMP)Carboxymethyl cellulose
Diethylenetriamine penta(methylene phosphonic acid) (DTPMP)
APPLIED CHEMICALS AND MATERIALS DIVISION
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ENGINEERED NANOPARTICLE SYSTEMS
Effect of stabilizer properties on Fe NP oxidation in water
200 nm
DTPMP prevents Fe NP oxidation in flowing water.
Stabilizer size and chelator strength appear to affect NP oxidation in water.
APPLIED CHEMICALS AND MATERIALS DIVISION
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ENGINEERED NANOPARTICLE SYSTEMS
Size Control of Bimetallic FeNi Nanoparticles
200 nm
100 nm
0.05 mol ATMP:mol Fe
0.8 mol ATMP:mol Fe
APPLIED CHEMICALS AND MATERIALS DIVISION
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ENGINEERED NANOPARTICLE SYSTEMS
0
0.04
0.08
0.12
0.16
0.2
Vis
cosi
ty (
Pa*
s)Membranes: How do nanoparticles change casting solution properties?
Viscosity: Higher viscosity tends to slow kinetics of phase inversion due to slower diffusion of solvent and non-solvent; slower demixing = reduction in macrovoids
No Nanoparticles
1% 5% 15% 25%
15% PES in DMAC
1% Nanoparticles
1% 5% 15% 25%
EtOH Vol. %EtOH Vol. %
APPLIED CHEMICALS AND MATERIALS DIVISION
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ENGINEERED NANOPARTICLE SYSTEMS
Cloud point measurement: Thermodynamic stability & polymer solubility
0
5
10
15
20
25
30
35
No
n-S
olv
en
t A
dd
ed
(m
l)
No Nanoparticles
1% 5% 15% 25%
15% PES in DMAC
1% Nanoparticles
EtOH Vol. %
1% 5% 15% 25%
EtOH Vol. %
Cloud point: Thermodynamic stability of solution – lower stability of polymer-solvent solution = lower polymer solubility, increased outflux of solvent and decreased influx of non-solvent = reduction in macrovoid formation
APPLIED CHEMICALS AND MATERIALS DIVISION
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ENGINEERED NANOPARTICLE SYSTEMS
Membrane lifetime: PES with iron nanoparticles
PES
1 µm2 µm
400 nm
Before filtration After filtration
After filtration
Significant flux decline & surface
degradation
100 nm
Before filtration
APPLIED CHEMICALS AND MATERIALS DIVISION
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ENGINEERED NANOPARTICLE SYSTEMS
Advanced Photon Source, Argonne Nat’l Lab: A Synchrotron Facility
Stats:
• Circumference: 3,622 ft. (0.69 miles)
• 35 experimental sectors• >1000 bending magnets• Electron energy:
• Linear accelerator: 450 MeV
• Booster synchrotron: 7 GeV
• X-rays: 3 keV – 100 keV
e-
X-rays
APPLIED CHEMICALS AND MATERIALS DIVISION
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ENGINEERED NANOPARTICLE SYSTEMS
X-Ray Absorption Spectroscopy (XAS)
Information Obtained:Element-specific chemical state: Coordination #, oxidation state
X-Ray Absorption Near Edge Structure (XANES)
Extended X-Ray Absorption Fine Structure (EXAFS)
X-Ray Absorption Spectroscopy (XAS)
Single Scattering:Who is my neighbor?-Atomic pair distribution-Modeling of interatomic distances
Multiple Scattering:Who is my neighbor?-First coordination sphere
http://en.wikipedia.org/wiki/XANEShttp://www.esrf.eu/UsersAndScience/Publications/Highlights/2000/surfaces/SU7.html
APPLIED CHEMICALS AND MATERIALS DIVISION
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ENGINEERED NANOPARTICLE SYSTEMS
High Energy X-Ray Diffraction (HE-XRD)
Wavelength:HE-XRD: 0.1 AngstromsPowder XRD: 1.54 Angstroms (CuKa)
Information Obtained:Structure: Atom pair distances, measures over multiple coordination spheres, allows modeling on nm scale
30 40 50 60 70 80 90
Fe-Ni
Ni Only
Inte
nsity
2-Theta (deg.)
Fe Only
2 3 4 5 6 7 8 9 10
-2.5
-2.0
-1.5
-1.0
-0.5
0.0
0.5
1.0
1.5
2.0
2.5
ATMP
HTPMP
DTPMP
Fe NPs
G(r
)
r (Å)
oxide
metal-metal
oxide
extended lattice structure, peak shifts suggest alloying/oxide
Powder XRD
APPLIED CHEMICALS AND MATERIALS DIVISION
ENGINEERED NANOPARTICLE SYSTEMSPDF Results for Peptide-Enabled Pd Nanoparticles
1 nm
Pd4 A6 A11
A6,11 C6 C11
C6,11 C6A11 A6C11
Clear sequence-dependence structural differences
APPLIED CHEMICALS AND MATERIALS DIVISION
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ENGINEERED NANOPARTICLE SYSTEMS
Viscosity: Effect of nanoparticles, pore former, and non-solvent
0
0.04
0.08
0.12
0.16
0.2
Vis
cosi
ty (
Pa*s
)
CMC
ATMP
No NPs
Higher viscosity tends to slow kinetics of phase inversion due to slower diffusion of solvent and non-solvent; slower demixing = reduction in macrovoids
15% PES 15% PES2% PVP
15% PES2% PVP5% EtOH
15% PES2% PVP25% EtOH
15% PES5% EtOH
15% PES25% EtOH
APPLIED CHEMICALS AND MATERIALS DIVISION
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ENGINEERED NANOPARTICLE SYSTEMS
Nanoparticle Catalysis
Lee and Sedlak. (2008) ES&T 42, 8528-8533.Chun et al. (2010) ES&T 44, 5079-5085.Alayoglu and Eichhorn (2008) JACS 130, 17479–17486.Sasaki et al. (2012) Nature Communications, 3, 1115.
Reduction of Carbon Tetrachloride
Oxygen Reduction Reaction for H2 fuel cells