Particle Processing Research

Terry A. Ring

Chemical Engineering

University of Utah

Presentation Goals

Introduce My Work to NSFShow Breadth of Coverage

Fundamentals of Ceramic Powder Processing and Synthesis

Product BoxShow Depth of Coverage in One Area

Nano-sized Cluster NucleationNSF - Program Vision

Ceramic Particle Processing Research

Crystallization Inhibitors - Trane Corp.

Nifedipine (Heart Drug) Sintering-Pfizer, Bayer

Scaling Chemicals-Spa Natural

Bio-Cements as Bone Replacement Materials - Sultzer, Mathis

Ceramic Thin Films As Chemical Sensors - RMA Associates

BaTiO3 Multi-layer Capacitors- Phillips(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

Reactant A Reactant B

Outlet

Overflow

Mixing �

Shaft Baffles

Nano-sized Cluster Nucleation

IntroductionClassical Nucleation Theory &

LimitationsNew Theory & Findings

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

Silicon Particles

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

Environmental remediation

Solar photocatalysis/fuel production

Environmental remediation

Solar photocatalysis/fuel production

0

100

200

300

400

500

600

700

800

3 4 5 6 7 8

Ab

sorb

ance

(25

0 n

m)

Elution Time (min)

MoS2 Photocatalyst

alkyl chloride

t=1 hour

t = 0

3 nm MoS2 nanocrystals photo-oxidizean alkyl chloride in solution using only visible room light

Fullerene Synthesis

Fullerene Synthesisodd vs. even clusters

Nanoparticle Synthesis

Desperate Need to Control and Scale-up!!

Nanoparticle Synthesis = Nucleation (no Growth!!)

Classical Nucleation Theory Free Energy in two pieces

G(r) = -(v r3/Vm)RT ln(S)+ a r2

G(i) = - i kBT lnS+ a ao2i2/3

where v(=vr3) is the volume and a(=ar2) is the area of the aggregate,is the molar volume of the precipitate, is the surface free energy per unit area.

X(atom) +X(r*-atom)<----> X(r*)CriticalSize, r*

G(i)

S

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

Numerical solution required except

ij = 1 Ck = • Smoluchowski, Physik Zeits, 17,557(1916)

ij= i+j Ck = , u= 1-exp(-t)

• Scott, W.T., J. Atmos. Sci., 25,54(1968)

ij=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).

1

1

)2/1(

)2/(

k

k

t

t

!

)exp())(1( 1

k

kukuu k

ii

kikiki

k

iikik CCCCtC

1,

1

1,2/1/

Collision Frequency

Jij= -(Dij Ci )/(ri+rj)*4(ri+rj)2*Cj *exp(-Gij/kBT)) = ij CiCj

This Collision Frequency compares to others by various Mechanisms:

Collision Frequencyij =

JijCiCj

Kolmogorovmicrolengthscale = /ueddy size = Tank size = L

Diffusion Dij*4 (ri+rj)Free Energy

-Dij exp( TkG

B

ij) 4

(ri+rj)

Viscous Shear 4/3• (ri +rj) 3 6/u <

Transition 2.36*5/12 -1/4

(ri+rj)8/36/u < < 25/u

Inertial 6.87*1/3 (ri+rj)7/3 25/u< < L/2

macro 7.09*(L)1/3 (ri+rj)2 L/2< ~L

Dij = µTkB6 *[

1ri +

1rj ] ri=ao*i1/3

Collision Free Energy, Gij

Gij =G(i+j)-(G(i)+G(j))

G(i) = - i kBT lnS + a ao2i2/3

i or j > 1Gij =G(i+j)-(G(i)+G(j))= a ao

2(i+j)2/3 - i2/3 - j2/3]

i = 1, any jGij = - i kBT lnS + a ao

2(i+j)2/3 - j2/3 ]

j = 1, any iGij = - j kBT lnS + a ao

2(i+j)2/3 - i2/3 ]

Effect of exp(-Gij/kBT) on Nucleation

ij=(i+j)exp(-Gij/kBT),Numerical Solution- C

ij=(i+j), Analytical Solution, N

Binding Energy per Li atomKouteckky, J. and Fantucci, P., Chem. Rev., 86,539-87(1986).

0 10 20

18.3358

-0

( )GSis

....4 a12

.kB T

ig

2

3 1

ig

.0 ig

201 ,is ig

Lin Optimal GeometryBE/n(eV)

Li3 3.2 (C2v) 0.35Li3 3.3 (C2v) 0.34*Li4 4.2(D4h) 0.51Li4 4.3(Td) 0.41Li5 5.2(D3h,C3v) 0.56Li5 5.3(C4v) 0.53Li5 5.4(D5h) -Li6 6.2(C5v) 0.62Li6 6.3(Oh) 0.60Li6 6.4(D3h) 0.63**Li7 7.2(C3v) 0.61Li7 7.3("fcc") 0.61Li7 7.4(??) -Li8 8.2(C2v) 0.71Li8 8.3("fcc") 0.65Li8 8.4("bcc") 0.60Li8 8.5(??) -

Cluster Binding Energy

Activation Energy for i+j Cluster

Calculated from EAi,j = [ ji

BE

*] -

ji

jj

BEii

BE oo

][

, [ji

BE

*]

values are taken from Table 3 using BE*i +.j

BE*corresponding

to a deformed structure of each cluster.

i / j 1 2 3 4 5 6 7 81 -kBT lnS0.34 0.51 0.56 0.62 0.61 0.71 0.652 - 0.41 0.53 0.60 0.61 0.65 0.65 -3 - - 0.63 0.61 0.60 0.65 - -4 - - - 0.60 0.65 - - -

Structural Classical

0 1 106

2 1063 10

60

0.5

1

C,m 1

N( ),.m t 1

C,m 2

N( ),.m t 2

.m t0 0.05 0.1

0

0.5

1

C,m 1

N( ),.m t 1

C,m 2

N( ),.m t 2

.m t

0 1 2 3 4 5 6 7 8 910

0.9999

4.63056e-33

N ,.tmax

2t k

C,

tmax

2k

N( ),.tmax t k

C,tmax k

9k0 1 2 3 4 5 6 7 8 910

1 1014

1 1013

1 1012

1 1011

1 1010

1 109

1 108

1 107

1 106

1 105

1 104

0.0010.01

0.11

,.tmax

2t k

,tmax

2k

( ),.tmax t k

,tmax k

1

k

New Nucleation Theory

Dramatic effect for stable clusters, k=2,4,8,… Magic Clusters

Magic Clusters Affects Synthesis PathNot One but Multiple Critical Cluster

Sizes Nucleation Rate, I= dCk*/dt

Depends on Synthesis Path

Crystalloluminescence

0 2 40

0.2

0.4

0.6

0.8

Collision Trajectory, R/re

BE

/ n

(eV

)

BE (i+j)

o

BE j

o BE i

o

+

BE j

BE i

+* *

²E

EACrystallo- luminescence

Figure 3 Collision trajectory for collision between i=3 and j=4 clusters,showing ground state energies before and after collision, as well as theactiviation energy of collsion.

Crystalloluminesent Spectrum

Intensity vs Energy Intensity =

collisions/per unit time = photons/unit time

Wavelength E = hc/l

Human eye detection @ 3x104photons/cm2/s at λ 510 nm

0 0.5 1 1.5 2 2.51 10

141 10

131 10

121 10

111 10

101 10

91 10

81 10

71 10

61 10

51 10

40.001

0.01

0.1

I,i k

E,i k

eV

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

Peak Count rates ~5-8x105 photons/s

Temporal & Spatial Bunching of Flashes

340nm<λ<380 nmFaint Blue White Light

Gibbon, M.A., Sopp, H. , Swanson, J., and Walton, A.J., J. Phys. C. 21,1921(1988).

Saturated NaCl + Conc. HCl - 120 s observation time

Spectra Has Series of Peaks

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)

BaSO4 Crystallization (20 min. exposure)Lines 1935Å-1945Å1976Å-1991Å2021Å-2037Å2145Å-2165Å2228Å-2300Å2300Å-2326Å

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

Nanocluster, Ti14C13 with emission peak at 20.1 microns is seen in Egg Nebula byA.G.G.M. Thielens and M.A. DuncanScience 288,313(2000)

this joins some 120 other small molecules identified in the vicinity of stars, interstellar gas and dust clouds

Experimental Verification

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 proposedfor FY01 Federal Budget

Usher in the “Next Industrial Revolution”

Develop and explore the “rules and tools” of nanotechnology

Education and SocietalImplications

President Clinton’s Jan. 21, 2000 announcementof a “National Nanotechnology Initiative” in a speech from the California Instituteof Technology.

Nanoscience -- behavior of materials at the nanoscale is Nothing like that at the large scale

Properties not predictable from those at large scale

Different physics and chemistry emerges

New phenomena associate with:

Lead to:Measured Yield Point

Light from Si

Catalysis from Pd clusters

GPa strength from Au

Pyrene hydrogenation

– Electronic confinement

– Preponderance of surfaces and interfaces

– Quantized effects

– 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

Many Particulate Problems in Nanotechnology

Lasers, CatalysisPhotonic Crystals - optical computingPhotonic Light PipesNano TiO2 Solar CellsNanotubes - computer wires, transistors Nanotube Light Emission - DisplaysNanocomposites - 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 PipeLight Leaving Pipe

Quantum Computing-

poly-Si

Si substrate

Light TrapsStopping Light without Absorption

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 Surfaces Particles Better BioCatalysis

Protein Binding Surfaces Particles Better Implants

1/4th of Catalyase Tetramer

Liver Enzyme

2 H2O2 ----> 2 H2O + O2(g)

Heam Site

Nano-particles for

Bio Separations/Bio Sensing

Couple to Computation

Nanoparticle properties from Computational QM

Particulate Generation in CFDMolecular AdsorptionMolecular BindingFractals + Flow

Conclusion

Particulate and Multiphase Program Bright Future

Many New Research Areas Many New Phenomena

Collaboration is key to SuccessVirtual Centers

• Nano Property Prediction• Photonic Crystals• Enzyme/Particle Binding• Fractal Aggregates• Nano Particle Synthesis

New properties abound at this small scale

microscale nanoscale

Inertia

• Turbulence, convection, and momentum are negligible

• Surface and interfacial properties play dominant role

• Electronics, optics, mechanics, chemistry

• Atomic forces and chemical bonds dominate

Quantized effects “rule”

New knowledge and understanding is neededNew knowledge and understanding is needed

Nanostructuring is Key to Novel/Enhanced Functionality

Layered-Structures Nanocrystals Nanocomposites

Electronics/photonics

Novel Magnets

Tailored hardness

Novel catalysts

Tailorable light emission

Supercapacitors

Separation membranes

Adaptive/responsive behavior

Pollutant/impurity gettering

Nanosciences will enable scientifically tailored materialsand lead to revolutionary advances in technology

Nanosciences will enable scientifically tailored materialsand lead to revolutionary advances in technology

Layered and 3-D StructuresYield New Optical Properties

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...

Vertical Cavity Surface Emitting Lasers (VCSELs)

Vertical Cavity Surface Emitting Lasers (VCSELs)Photonic LatticesPhotonic Lattices

Optical signals guided through narrow channels and around sharp corners

Near 100% transmission

Key technology for telecommunications and optical computing

A

2-D

B

3-D

poly-Si

Si substrate

Water Condensation due to Shock Wave

Deep Sea Life

Salt Lake Tribune, 2/13/97National Geographic October 2000

Deep Sea Vents

C&E News 12/21/98National Geographic October 2000

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!!