final presentation gimena gordillo xavier hailey · ventosa, n. et al. “depressurization of an...

Nanopowder ProductionA Comparison of Several Methods

Gimena GordilloXavier Hailey

Advisors: Prof. G. A. MansooriGrad. Student Listowel Agyarko

NSF-REU University of Illinois at Chicago Summer 2004


Outline

Introduction to Nanotechnology1. What is Nanotechnology 2. Nanostructures3. The Importance of Nanotechnology4. Applications of Nanotechnology

Research1. Objectives2. Crystallization3. Nanopowder Production Techniques


What is Nanotechnology?

Research and Development in the length scale of 1 - 100 nanometer range.

Build micro and macro materials and products with atomic precision.


Nanostructures


Importance of Nanotechnology

Nanoscale variations’ effects on atomic structure.

Conduction properties

Higher density than microstructures.

High surface to volume ratio.


Applications of Nanotechnology

“Robots” in Living Systems

Electronics

Catalysts

Information Storage Capacity

Pharmaceuticals


Applications of Nanotechnology

Comparison between micro and nano Molybdenum


Nanopowders

ApplicationsPharmaceuticalsPigmentsPolymers

Particle FormationChemical RoutesPhysical Methods


Nanopowder Production

Disadvantages of Conventional Methods of Powder Production

Particle Size CharacteristicsEnergy CostsMaterial Liabilities

Supercritical Fluids as an AlternativeBetter Particle Size CharacteristicsLower Energy Costs“Milder” Process


Crystallization

β= concentration /super-saturation concentration

Nucleation vs. Crystal Growth

Effects on the size distribution of particles Fig.1. Time vs. Supersaturation Ratio [7]

RESEARCH


Objectives

Study and compare nanopowder production techniques

Rapid Expansion of Supercritical Solutions (RESS)Supercritical Anti-solvent (SAS)Particle from Gas Saturated Solutions (PGSS)Depressurization of an Expanded Liquid Organic Solution (DELOS)


Rapid Expansion of Supercritical Solutions (RESS)

ApplicationsPharmaceuticalsEncapsulation

Driving ForcePressure gradient in the nozzle

Description of Process1. Dissolution of Solute2. Rapid Depressurization

2


RESS Process

2


Rapid Expansion of Supercritical Solutions (RESS)

Working Condition Change EffectsTemperature and Pressure

AdvantagesOrganic Solvent not required No Environment Hazard

DisadvantagesSeveral families are not soluble in CO2


Supercritical Anti Solvent (SAS)

ApplicationsPharmaceuticalsPolymers & BiopolymersCatalysts

Driving ForceSupersaturation Ratio, β>1

Description of Process1. Dissolution 2. Mixing & Crystallization3. Stripping


SAS Process

LiquidCO2cylinder

Heat Exchanger

Mixing device

Collectingbasket

Solution vessel

Pump


Supercritical Antisolvent(SAS)

Working Condition Change EffectsSmall Effects from Pressure and TemperatureMixing and Droplet Formation in Nozzle

Advantages Formation of ParticlesSolubilityLarge range of materialsEasy Removal of Antisolvent

DisadvantagesRemoval of Solvent


Particles from Gas Saturated Solutions (PGSS)

ApplicationsPharmaceuticals, Including Lipids

Driving ForceLarge Drop from Working Pressure to Atmospheric Pressure

Description of Process 1. Melting of Solvent Under Pressure2. Expansion of Solution Through Nozzle


PGSS ProcessMixing Vessel

ExpansionVessel

Recycle

CO2

Solvent Reservoir

CO2

Pump Nozzle

Recycle


Particles from Gas Saturated Solutions (PGSS)

Working Condition Change EffectsPressure Effects on Morphology and Aggregation

AdvantagesBroad Range of MaterialsSolvent-free ProcessAllows for Encapsulation & Micro Composites

DisadvantagesSCF Dissolution


PGSS

SEM images of Theophylline/HPO composite particles formed by PGSS process at 359 K and a. 18 MPa b. 14 MPa to atmospheric conditions [6].


Depressurization of an Expanded Liquid Organic Solution (DELOS)

ApplicationsDyes and Chemical IntermediatesSpecialty Polymers & Explosives

Driving ForceLarge Temperature Gradient

Description of Process 1. Dissolution2. Pressurization3. Expansion


DELOS Process

CO2

NO2

ExpansionVessel

SeparationVessel

Mixing Vessel

Pump

Solvent Reservoir

Recycle


Working Condition Change EffectsWorking Pressure & Flow RateParticle Characteristics & solubility ratio.

AdvantagesMild ProcessAllows for Encapsulation

DisadvantagesSolubility Limit to Process

Depressurization of an Expanded Liquid Organic Solution (DELOS)


DELOS

SEM images of particles produced by DELOS process [


Conclusions

YesYesYesYesEncapsulation

micro & nanomicro & nanomicro & nanomicro & nanoParticle Size

3 Steps2 Steps3 Steps2 StepsLength of Procedure

SCFHighestSCFSCFWorking Temperature Dependence

SCFMorphologySCFSCFWorking Pressure Dependence

TemperatureTemperatureSolubilityPressureDriving Force

Co-SolventSoluteAnti-Solvent SolventRole of SCF

Larger Mol.High PuritySmall Mol.Small Mol.Applications

DELOSPGSSSASRESS


Conclusions

Selection of ProcessSupercritical Fluid Interaction With Desired Product

Desired Product Characteristics

Capital and Operational Costs


Future Work

Development of Computational Models

Building of Experimental Setups

Production of Products

Analysis of Products


Acknowledgements

Prof. G. A. Mansoori

Graduate Student Listowel Agyarko

Prof. R. Turian

NSF for Financial Support


References1. Mansoori, G. A. “Advances in Atomic & Molecular

Nanotechnology.”2. www.nano.gov3. http://www.nyu.edu/pages/mathmol/library/carbon/fullerene.gif4. www.climaxmolybdenum.com/ NanoMo.htm5. Fages, J. et al. “Particle Generation for Pharmaceutical

Applications Using Supercritical Fluid Technology.”6. Rodrigues, M. et al. “Microcomposites

theophylline/hydrogenated palm oil from a PGSS process for controlled drug delivery systems.”

7. Ventosa, N. et al. “DELOS Process: a crystallization technique using compressed fluids1. comparison to the GAS crystallization method.”

8. Ventosa, N. et al. “Depressurization of an Expanded Liquid Organic Solution (DELOS): A New Produce for Obtaining Submicron or Micron Sized Crystalline Particles.”

Questions?

final presentation gimena gordillo xavier hailey · ventosa, n. et al. “depressurization of an...

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