Particle Processing
Research
Terry A. Ring
Chemical Engineering
University of Utah
Presentation Goals
Introduce My Work to NSF
Show Breadth of Coverage
Fundamentals of Ceramic Powder Processing
and Synthesis
Product Box
Show Depth of Coverage in One Area
Nano-sized Cluster Nucleation
NSF - Program Vision
Ceramic Particle
Processing Research
Crystallization
Inhibitors Trane Corp.
Nifedipine (Heart
Drug) Sintering-Pfizer,
Bayer
Scaling ChemicalsSpa Natural
Bio-Cements as Bone
Replacement
Materials - Sultzer,
Mathis
Ceramic Thin Films As
Chemical Sensors RMA Associates
BaTiO3 Multi-layer
CapacitorsPhillips(Taiwan)
Ceramic Particle
Processing Research-con’t
Multi-layer Chip
Support Sintering Metalor, IBM, Dupont
Vermiculite Based
Insulation Materials ABB
Silica Aerogels for
Building Insulation Airglass, SA
Nitride coating for
Al2O3 Platelets for
Cutting Tools Amysa, SA
Pultrusion Process for
Carbon Fiber
Reinforced Composite
- Easton
Precipitation Research
Agglomeration in CSTR
M ixing•
Ba ff le s
R ea c ta nt A
S ha f t
R ea c ta nt B
O utle t
O ver f low
Nano-sized Cluster
Nucleation
Introduction
Classical Nucleation Theory & Limitations
New Theory & Findings
Silicon Particles
Introduction
Unique Properties of Nanosized Particles
Plasmon Resonance -color due to size, color
change due to adsorption-sensors
Between Bulk and Atomic Electrical Properties
Catalytic Properties
Magic Cluster Sizes
C60, C70, C nanotubes,
Na clusters of 8, 20, 40, 58 and 92
Stimulated Emission CdS
Nano-Clusters-Laser
 Lasing only when quantum
dot concentration is
sufficiently high.
 Stimulated emission>Auger
recombination
 Klimov, V. Mikhailovsky,
A.,Xu, S., Hollingswork, J.,
Malko, A., Bawendi, M.,
Eiser, H-J., Leatherhead,
C.A.
 Science 290,314 (2000)
 Science 287,1011 (2000)
Semiconductor Nanocrystals
Breakdown Organic Pollutants
800
Absorbance (250 nm)
700
MoS
600
500
2
Photocatalyst
t=1 hour
400
300
200
alkyl chloride
100
t=0
0
3
4
5
6
Elution Time (min)
7
8
3 nm MoS2 nanocrystals photo-oxidize
an alkyl chloride in solution using only
visible room light
 Environmental remediation
 Solar photocatalysis/fuel production
Fullerene Synthesis
Fullerene Synthesis
odd vs. even clusters
Nanoparticle Synthesis
Desperate Need to Control
and Scale-up!!
Nanoparticle Synthesis =
Nucleation (no Growth!!)
324.897
Classical Nucleation Theory
G(i)
G( i , 1 )
kB . T
 Free Energy in two pieces
G(r) = -(bv r3/Vm)RT ln(S)+ g ba r2
G(i) = - i kBT lnS+ g ba ao2 i2/3
where v(=bvr3) is the volume and
a(=bar2) is the area of the aggregate,is
the molar volume of the precipitate, g is
the surface free energy per unit area.
X(atom) +X(r*-atom)<----> X(r*)
G( i , 10 )
kB . T
S
G( i , 50 )
kB . T
G( i , 100 )
kB . T
G( i , 500 )
kB . T
G( i , 1000 )
kB . T
0
G( i , 5000 )
kB . T
Critical
Size, r*
G( i , 10000 )
kB . T
0
10
20
30
i
40
50
New Nucleation Theory
 Multi-Atom Addition
 Free Energy Driving Force for Diffusion and
Addition
New Attributes
Predicts transients of Cluster Size Distribution
 Predicts Induction Time
Population Balance
- Multi-atom Addition

k 1

i 1
i 1
Ck / t  1 / 2 li ,k i Ci Ck i  Ck  li ,k Ci
Numerical solution required except
lij = 1 Ck =
(t / 2) k 1
(1  t / 2) k 1
• Smoluchowski, Physik Zeits, 17,557(1916)
lij= i+j Ck =
(1  u)(ku) k 1 exp( ku)
, u= 1-exp(-t)
k!
• Scott, W.T., J. Atmos. Sci., 25,54(1968)
lij=i*j Ck = tk-1 kk-2 exp(-k t)/k!, t  0
• McLeod, J.B., Quant, J. Math Oxford, 13,119 and 193(1962).
Collision Frequency
Jij= -(Dij Ci )/(ri+rj)*4(ri+rj)2*Cj *exp(-Gij/kBT)) = lij CiCj
This Collision Frequency compares to others by various Mechanisms:
Kolmogorov
Jij
Collision Frequency
microlength
lij = C C
scale = /u
i j
eddy size = 
Tank size = L
Diffusion
Dij*4 (ri+rj)
Gij
Free Energy
-Dij exp( k B T ) 4
Inertial
(ri+rj)
• (r +r ) 3
4/3g
i
j
5/12
2.36*
 -1/4
(ri+rj)8/3
6.87*1/3 (ri+rj)7/3
macro
7.09*(L)1/3 (ri+rj)2
Viscous Shear
Transition
k BT
1 1
Dij = 6µ *[ + ]
ri rj
ri=ao*i1/3
6/u < 
6/u <  < 25/u
25/u<  < L/2
L/2<  ~L
Collision Free Energy, Gij
Gij =G(i+j)-(G(i)+G(j))
G(i) = - i kBT lnS + g ba ao2 i2/3
i or j > 1
Gij =G(i+j)-(G(i)+G(j))= g ba ao2 [(i+j)2/3 - i2/3 - j2/3]
i = 1, any j
Gij
=
- i kBT lnS + g ba ao2 [(i+j)2/3 - j2/3 ]
j = 1, any i
Gij
=
- j kBT lnS + g ba ao2 [(i+j)2/3 - i2/3 ]
Effect of exp(-Gij/kBT) on Nucleation
lij=(i+j)exp(-Gij/kBT),
Numerical Solution- C
lij=(i+j),
Analytical Solution, N
Binding Energy per Li atom
Kouteckky, J. and Fantucci, P., Chem. Rev., 86,539-87(1986).
18.3358
(
GS )
is
2
3
2
4 . . a1 . g . ig
kB. T
ig
1
0 . ig
-0
0
1
10
is , ig
20
20
Cluster Binding Energy
Lin
Li3
Li3
Li4
Li4
Li5
Li5
Li5
Li6
Li6
Li6
Li7
Li7
Li7
Li8
Li8
Li8
Li8
Optimal Geometry
3.2 (C2v)
3.3 (C2v)
4.2(D4h)
4.3(Td)
5.2(D3h,C3v)
5.3(C4v)
5.4(D5h)
6.2(C5v)
6.3(Oh)
6.4(D3h)
7.2(C3v)
7.3("fcc")
7.4(??)
8.2(C2v)
8.3("fcc")
8.4("bcc")
8.5(??)
BE/n
(eV)
0.35
0.34*
0.51
0.41
0.56
0.53
0.62
0.60
0.63**
0.61
0.61
0.71
0.65
0.60
-
Activation Energy for i+j Cluster
BE o
BE o
[
i
j]
i
j
BE *
BE *
Calculated from EAi,j = [
],[
]
i j
i j
i j
BE *
BE*
values are taken from Table 3 using i +.
corresponding
j
to a deformed structure of each cluster.
i/j
1
2
3
4
1
-kBT lnS
-
2
0.34
0.41
-
3
0.51
0.53
0.63
-
4
0.56
0.60
0.61
0.60
5
0.62
0.61
0.60
0.65
6
0.61
0.65
0.65
-
7
0.71
0.65
-
8
0.65
-
Structural
Classical
1
C
1
C
m, 1
m, 1
N( m. t , 1 )
0.5
C
m, 2
N( m. t , 1 )
0.5
C
m, 2
N( m. t , 2 )
N( m. t , 2 )
0
0
1 10
6
2 10
m.  t
6
6
3 10
0.9999
N
C
tmax .
t , k
2
tmax
,k
2
N( tmax . t , k )
C
tmax , k
4.63056e-33
0 1 2 3 4 5 6 7 8 910
k
9
0
1
0.1
0.01
tmax .
0.001
t , k
4
2
1 10
5
1 10
6
tmax
1 10
,k
7
1 10
2
8
1 10
( tmax . t , k ) 1 10 9
10
1 10
11
tmax , k
1 10
12
1 10
13
1 10
14
1 10
0
0.05
m.  t
0.1
1
0 1 2 3 4 5 6 7 8 910
k
New Nucleation Theory
Dramatic effect for stable clusters,
k=2,4,8,…
 Magic Clusters
Magic Clusters Affects Synthesis Path
Not One but Multiple Critical Cluster Sizes
Nucleation Rate, I= dCk*/dt
Depends on Synthesis Path
Crystalloluminescence
0.8
o
BE/ n (eV)
BE
(i+j)
0.6
o
BE + BE
i
j
²E
Crystallolumines cen ce
0.4
o
EA
BE *+ BE*
i
j
0.2
0
0
2
Collision Trajectory, R/r
Figure 3 Collision trajectory for collision between i=3 and j=4 clusters,
showing ground state energies before and after collision, as well as the
activiation energy of collsion.
4
e
Crystalloluminesent
Spectrum
Intensity vs Energy
Intensity =
0.1
0.01
0.001
collisions/per unit time =
photons/unit time
Wavelength E = hc/l
1 10
1 10
1 10
I
i, k
1 10
1 10
1 10
1 10
1 10
Human eye detection
3x104photons/cm2/s
@
λ 510 nm
at
1 10
1 10
1 10
4
5
6
7
8
9
10
11
12
13
14
0
0.5
1
1.5
E
i, k
eV
2
2.5
Similar to Line Spectra
Is this another cold fusion?
An effect produced by a barely detectable cause.
Data on the edge of detectability
Measurements are attributed to greater accuracy
Fantastic theories are offered.
Criticisms are met by ad hoc excuses thought up
on the spur of the moment.
The ratio of supporters to critics rises up to
~50% and then falls gradually to oblivion.
From1953 Lecture by Irving Langmuir
Another cold fusion? Cont.
Researcher avoids designing experiments that
would confirm whether or not an effect actually
exists. (D. Rousseau, 1982).
Pressures to publish prematurely (Broad, W. and
Wade, N., 1982.)
• Being scooped.
• Notoriety.
• Potential for money to be made.
More common in fields with reliance on
statistically weak data. (N. Turro, 2001)
Crystalloluminescence
• Term Schoenwald in 1786
30 References 1786 and 1957
• “An understanding of crystalloluminescence in not too
satisfactory at the present time,” E.N. Harvey 1957
Examples:
NaCl, KCl, NaF, AsCl3, K2SO4, As3O3, Sr(NO3)2,, CoSO4, K2CO3, KHSO3, NaKSO4,
NaKCrO4, NaKSeO4, Na2SO4, benzoic acid, and ice, water.
16 References 1957-1991 (15 Russian, 1 US + 1 Italian Review)
 “It is not possible to … provide either a unifying physical picture of the microscopic mechanism
governing (crystalloluminescence) or a physical rule that allows conditions...where the
phenomenon is stronger,” Barsanti, M. & Maccarrone,F., 1991
3 References from 1991-2000 (2 India, 1 Russian) - Experiments
Experimental Observations
 Delay time is a function
of concentration & mixing
Flashes are Short
< 80 ns
Saturated NaCl + Conc. HCl - 120 s observation time
Peak Count rates
~5-8x105 photons/s
Gibbon, M.A., Sopp, H. , Swanson, J., and Walton, A.J., J. Phys. C. 21,1921(1988).
Temporal & Spatial
Bunching of Flashes
340nm<λ<380 nm
Faint Blue White Light
Spectra Has Series of Peaks
BaSO4 Crystallization
(20 min. exposure)
Lines
1935Å-1945Å
1976Å-1991Å
2021Å-2037Å
2145Å-2165Å
2228Å-2300Å
2300Å-2326Å
 Lines are Different from
Thermal
Luminescence
Photoluminescence
 Impurities in Crystal have
a Big Effect on Spectrum
Rabinerson, A.I. Wladimirskaya, M.A., Acta Physicochimica URSS, 10,859(1939)
New Theory’s Predictions
Predicts Crystalloluminescent Spectrum
Method to Quantitatively Measure Nucleation
Potential Real World Examples
H2O Condensation Nucleation
Interstellar Dust Nano-nucleation
Light from Deep Sea Vents
Super Novae
Experimental Verification
Nanocluster, Ti14C13
with emission peak at 20.1 microns
is seen in Egg Nebula by
A.G.G.M. Thielens and M.A. Duncan
Science 288,313(2000)
this joins some 120 other small molecules
identified in the vicinity of stars,
interstellar gas and dust clouds
Interstellar Dust Clouds - Light from the Fringe
- Crystalloluminescence due to Nanocluster Nucleation
NSF
Particulate and Multiphase Program
1. Aerosols and colloids
2. Nanostructures
3. Granular flows
4. Multiphase processes related to particles,
droplets, and bubbles
5. Hydrodynamical multiphase analysis
6. Specific tools
Nanotechnology has
acquired National Status
 National Nanotechnology
Initiative $500M proposed
for FY01 Federal Budget
 Usher in the “Next Industrial
Revolution”
 Develop and explore the
“rules and tools” of
nanotechnology
 Education and Societal
Implications
President Clinton’s Jan. 21, 2000 announcement
of a “National Nanotechnology Initiative”
in a speech from the California Institute
of Technology.
Nanoscience -- behavior of materials
at the nanoscale is Nothing like that at the
large scale
 Properties not predictable from those at large scale
Light from Si
 Different physics and chemistry emerges
 New phenomena associate with:
Catalysis from Pd clusters
– Electronic confinement
– Preponderance of surfaces
and interfaces
– Quantized effects
Pyrene hydrogenation
GPa strength from Au
Lead to:
– New modes of electronic and thermal transport
– Different manifestations of thermodynamic
properties, phase transitions, and collective
phenomena
– New chemical reactivities
– New mechanical properties--strength,
friction, wear
Measured Yield Point
Many Particulate Problems
in Nanotechnology
Lasers, Catalysis
Photonic Crystals - optical computing
Photonic Light Pipes
Nano TiO2 Solar Cells
Nanotubes - computer wires, transistors
Nanotube Light Emission - Displays
Nanocomposites - tunable lasers
Layered Structures
Taylored Materials

Electronics/photonics

Novel Magnets

Tailored hardness
Defects in Ordered Arrays
Bend Light
Optical Semiconductors
Hexagonal Packing of
Spheres
Light Diffraction
Photonic Crystal Light Pipe
Light Pipe
Light Leaving Pipe
Quantum Computing-
Light Traps
Stopping Light without Absorption
poly-Si
Si substrate
Yablonovitch, E., 1986.
Coupling to Biology
Sol-gel (or Micelle structures) for drug
delivery
Diffusive Collisions ~ R(DF+2-3)
Diffusing Species will Stay in Fractal when DF >1.0
Barbe, C., 2001 Australian Patent Application
Connection to Biology
Enzyme Binding
1/4th of Catalyase Tetramer
Surfaces
Particles
Better BioCatalysis
Protein Binding
Surfaces
Particles
Better Implants
Heam
Site
Liver Enzyme
2 H2O2 ----> 2 H2O + O2(g)
Nano-particles for
Bio Separations/Bio Sensing
Couple to Computation
Nanoparticle properties from
Computational QM
Particulate Generation in CFD
Molecular Adsorption
Molecular Binding
Fractals + Flow
Conclusion
Particulate and Multiphase Program
Bright Future
Many New Research Areas
Many New Phenomena
Collaboration is key to Success
Virtual Centers
•
•
•
•
•
Nano Property Prediction
Photonic Crystals
Enzyme/Particle Binding
Fractal Aggregates
Nano Particle Synthesis
New properties abound at this
small scale
microscale
Inertia
nanoscale
Quantized effects
“rule”
• Turbulence, convection, and
momentum are negligible
• Electronics, optics,
mechanics, chemistry
• Surface and interfacial
properties play dominant
role
• Atomic forces and
chemical bonds dominate
New knowledge and understanding is needed
Nanostructuring is Key
to Novel/Enhanced Functionality
Layered-Structures
Nanocrystals
Nanocomposites
 Electronics/photonics
 Novel catalysts
 Separation membranes
 Novel Magnets
 Tailorable light emission
 Adaptive/responsive behavior
 Tailored hardness
 Supercapacitors
 Pollutant/impurity gettering
Nanosciences will enable scientifically tailored materials
and lead to revolutionary advances in technology
Layered and 3-D Structures
Yield New Optical Properties
Vertical Cavity Surface
Emitting Lasers (VCSELs)
Photonic Lattices
A
2-D
B
poly-Si
Si substrate
3-D
 Optical signals guided through narrow
channels and around sharp corners
 Near 100% transmission
 Key technology for
telecommunications and optical
computing
 The VCSEL is to photonics what the
transistor was to electronics. A key
21st century technology
 Most efficient, low-power light source
(57% in ‘97)
 Applications in optical
communications, scanners, laser
printing, computing...
Water Condensation due to Shock Wave
Deep Sea
Life
Salt Lake Tribune, 2/13/97
National Geographic October 2000
Deep Sea Vents
National Geographic October 2000
C&E News 12/21/98
Deep Sea Vents
Deep Sea Vents Spew Solublized Salts into
the cold sea, causing Precipitation &
Crystalloluminescence
In the Deep Ocean Deep Sea Vents are the
only source of Chemical Energy and Food
Mobile Animals need to be able to locate
them - so they need eyes!!