Particle Processing ResearchTerry A. RingChemical EngineeringUniversity of Utah

Presentation GoalsIntroduce My Work to NSFShow Breadth of CoverageFundamentals of Ceramic Powder Processing and SynthesisProduct BoxShow Depth of Coverage in One AreaNano-sized Cluster NucleationNSF - Program Vision

Ceramic Particle Processing ResearchCrystallization Inhibitors - Trane Corp.Nifedipine (Heart Drug) Sintering-Pfizer, BayerScaling Chemicals-Spa NaturalBio-Cements as Bone Replacement Materials - Sultzer, MathisCeramic Thin Films As Chemical Sensors - RMA AssociatesBaTiO3 Multi-layer Capacitors- Phillips(Taiwan)

Ceramic Particle Processing Research-contMulti-layer Chip Support Sintering - Metalor, IBM, DupontVermiculite Based Insulation Materials - ABBSilica Aerogels for Building Insulation - Airglass, SANitride coating for Al2O3 Platelets for Cutting Tools - Amysa, SAPultrusion Process for Carbon Fiber Reinforced Composite - Easton

Precipitation Research

Agglomeration in CSTR

Nano-sized Cluster NucleationIntroductionClassical Nucleation Theory & LimitationsNew Theory & Findings

IntroductionUnique Properties of Nanosized ParticlesPlasmon Resonance -color due to size, color change due to adsorption-sensorsBetween Bulk and Atomic Electrical PropertiesCatalytic Properties Magic Cluster SizesC60, C70, C nanotubes, Na clusters of 8, 20, 40, 58 and 92

Silicon Particles

Stimulated Emission CdS Nano-Clusters-LaserLasing 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 PollutantsEnvironmental remediationSolar photocatalysis/fuel production3 nm MoS2 nanocrystals photo-oxidize an alkyl chloride in solution using only visible room light

Fullerene Synthesis

Fullerene Synthesisodd vs. even clusters

Nanoparticle SynthesisDesperate Need to Control and Scale-up!!

Nanoparticle Synthesis = Nucleation (no Growth!!)Classical Nucleation Theory 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*)CriticalSize, r*G(i)S

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New Nucleation Theory Multi-Atom Addition Free Energy Driving Force for Diffusion and AdditionNew Attributes Predicts transients of Cluster Size Distribution Predicts Induction Time

Population Balance - Multi-atom Addition Numerical solution required except lij = 1Ck = Smoluchowski, Physik Zeits, 17,557(1916)lij= i+jCk = , u= 1-exp(-t)Scott, W.T., J. Atmos. Sci., 25,54(1968)lij=i*jCk = tk-1 kk-2 exp(-k t)/k!, t 0McLeod, J.B., Quant, J. Math Oxford, 13,119 and 193(1962).

Collision Frequency

Collision Free Energy, GijGij =G(i+j)-(G(i)+G(j))G(i) = - i kBT lnS + g ba ao2 i2/3 i or j > 1Gij =G(i+j)-(G(i)+G(j))= g ba ao2 [(i+j)2/3 - i2/3 - j2/3] i = 1, any jGij = - i kBT lnS + g ba ao2 [(i+j)2/3 - j2/3 ] j = 1, any iGij = - j kBT lnS + g ba ao2 [(i+j)2/3 - i2/3 ]

Effect of exp(-Gij/kBT) on Nucleationlij=(i+j)exp(-Gij/kBT),Numerical Solution- Clij=(i+j), Analytical Solution, N

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

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Cluster Binding Energy

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Lin

Optimal Geometry

BE/n

(eV)

Li3

3.2 (C2v)

0.35

Li3

3.3 (C2v)

0.34*

Li4

4.2(D4h)

0.51

Li4

4.3(Td)

0.41

Li5

5.2(D3h,C3v)

0.56

Li5

5.3(C4v)

0.53

Li5

5.4(D5h)

-

Li6

6.2(C5v)

0.62

Li6

6.3(Oh)

0.60

Li6

6.4(D3h)

0.63**

Li7

7.2(C3v)

0.61

Li7

7.3("fcc")

0.61

Li7

7.4(??)

-

Li8

8.2(C2v)

0.71

Li8

8.3("fcc")

0.65

Li8

8.4("bcc")

0.60

Li8

8.5(??)

-

Activation Energy for i+j Cluster

Calculated from EAi,j = [

] -

, [

] values are taken from Table 3 using EQ \F(BE*,i) +.

corresponding to a deformed structure of each cluster.

i / j

1

2

3

4

5

6

7

8

1

-kBT lnS

0.34

0.51

0.56

0.62

0.61

0.71

0.65

2

-

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

-

-

-

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Structural Classical

New Nucleation TheoryDramatic effect for stable clusters, k=2,4,8, Magic ClustersMagic Clusters Affects Synthesis PathNot One but Multiple Critical Cluster Sizes Nucleation Rate, I= dCk*/dtDepends on Synthesis Path

Crystalloluminescence

Crystalloluminesent SpectrumIntensity vs EnergyIntensity = collisions/per unit time = photons/unit time Wavelength E = hc/l

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

Similar to Line Spectra

Is this another cold fusion?An effect produced by a barely detectable cause.Data on the edge of detectabilityMeasurements are attributed to greater accuracyFantastic 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)

CrystalloluminescenceTerm Schoenwald in 178630 References 1786 and 1957 An understanding of crystalloluminescence in not too satisfactory at the present time, E.N. Harvey 1957Examples: 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., 19913 References from 1991-2000 (2 India, 1 Russian) - Experiments

Experimental ObservationsDelay time is a function of concentration & mixingFlashes are Short < 80 ns Peak Count rates ~5-8x105 photons/sTemporal & Spatial Bunching of Flashes340nm

Spectra Has Series of PeaksLines are Different from Thermal LuminescencePhotoluminescenceImpurities in Crystal have a Big Effect on SpectrumRabinerson, A.I. Wladimirskaya, M.A., Acta Physicochimica URSS, 10,859(1939)BaSO4 Crystallization (20 min. exposure)Lines 1935-19451976-19912021-20372145-21652228-23002300-2326

New Theorys PredictionsPredicts Crystalloluminescent SpectrumMethod to Quantitatively Measure Nucleation

Potential Real World ExamplesH2O Condensation NucleationInterstellar Dust Nano-nucleationLight 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 cloudsExperimental Verification

Interstellar Dust Clouds - Light from the Fringe - Crystalloluminescence due to Nanocluster Nucleation

NSFParticulate and Multiphase Program1. Aerosols and colloids2. Nanostructures3. Granular flows4. Multiphase processes related to particles, droplets, and bubbles5. Hydrodynamical multiphase analysis6. Specific tools

Nanotechnology has acquired National StatusNational Nanotechnology Initiative $500M proposed for FY01 Federal BudgetUsher in the Next Industrial RevolutionDevelop and explore the rules and tools of nanotechnologyEducation and Societal Implications President Clintons Jan. 21, 2000 announcementof 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 scaleProperties not predictable from those at large scale

Different physics and chemistry emerges

New phenomena associate with:Lead to:Measured Yield PointLight from SiCatalysis from Pd clustersGPa strength from AuPyrene 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 NanotechnologyLasers, CatalysisPhotonic Crystals - optical computingPhotonic Light PipesNano TiO2 Solar CellsNanotubes - computer wires, transistors Nanotube Light Emission - DisplaysNanocomposites - tunable lasers

Layered StructuresTaylored MaterialsElectronics/photonicsNovel MagnetsTailored hardness

Defects in Ordered Arrays Bend LightOptical Semiconductors

Hexagonal Packing of SpheresLight Diffraction

Photonic Crystal Light PipeLight PipeLight Leaving Pipe

Quantum Computing-Light TrapsStopping Light without AbsorptionYablonovitch, E., 1986.

Coupling to BiologySol-gel (or Micelle structures) for drug deliveryDiffusive Collisions ~ R(DF+2-3)Diffusing Species will Stay in Fractal when DF >1.0

Barbe, C., 2001 Australian Patent Application

Connection to BiologyEnzyme BindingSurfacesParticlesBetter BioCatalysisProtein BindingSurfacesParticlesBetter Implants1/4th of Catalyase TetramerLiver Enzyme2 H2O2 ----> 2 H2O + O2(g)Heam Site

Nano-particles for Bio Separations/Bio Sensing

Couple to ComputationNanoparticle properties from Computational QMParticulate Generation in CFDMolecular AdsorptionMolecular BindingFractals + Flow

ConclusionParticulate and Multiphase ProgramBright FutureMany New Research Areas Many New PhenomenaCollaboration is key to SuccessVirtual CentersNano Property PredictionPhotonic CrystalsEnzyme/Particle BindingFractal AggregatesNano Particle Synthesis

New properties abound at this small scalemicroscalenanoscale 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 ruleNew knowledge and understanding is needed

Nanostructuring is Key to Novel/Enhanced FunctionalityLayered-StructuresNanocrystalsNanocompositesElectronics/photonicsNovel MagnetsTailored hardnessNovel catalystsTailorable light emissionSupercapacitorsSeparation membranesAdaptive/responsive behaviorPollutant/impurity getteringNanosciences will enable scientifically tailored materials and lead to revolutionary advances in technology

Layered and 3-D StructuresYield New Optical PropertiesThe VCSEL is to photonics what the transistor was to electronics. A key 21st century technologyMost efficient, low-power light source (57% in 97)Applications in optical communications, scanners, laser printing, computing...Vertical Cavity Surface Emitting Lasers (VCSELs)Photonic LatticesOptical signals guided through narrow channels and around sharp cornersNear 100% transmissionKey technology for telecommunications and optical computingA2-DB3-D

Water Condensation due to Shock Wave

Deep Sea LifeSalt Lake Tribune, 2/13/97National Geographic October 2000

Deep Sea VentsC&E News 12/21/98National Geographic October 2000

Deep Sea VentsDeep Sea Vents Spew Solublized Salts into the cold sea, causing Precipitation & CrystalloluminescenceIn 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!!