Supercritical Fluid Assisted Particle Synthesis

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Supercritical Fluid Assisted Particle Synthesis

• Antoinette Kretsch
• New Jersey Institute of Technology

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Supercritical Fluid Extraction
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Analysis Techniques

• Beckman Coulter N4 Plus Submicron Particle Size
  Analyzer
• determines particle size by measuring the rate of
  change in laser light intensity scattered by
  particles as they diffuse through a fluid
• Leo 1530 VP SEM Microscope
• Produces 3-D image magnified x100,000 by spraying
  specimen with fine metal coating and sending beam
  of electrons over the surface to be projected
  onto fluorescent screen 
• SigmaScan Systat software program
• Collects data such as diameter and area of
  nanoparticles using pictures taken by the SEM
• FTIR Fourier Transform Infrared Spectroscopy
• Used to identify chemical bonds in various
  substances by interpreting the infrared
  absorption spectra

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Conclusions

• A smaller nozzle will yield smaller, less
  agglomerated particles
• A pressure closer to supercritical pressure (78
  bar for CO2) will yield smaller particles, so 82
  bar had smaller particles than 100 bar
• The higher ratio of acetone to DCM will yield
  smaller particles with a narrow size distribution
  although the particles will have a distorted
  shape

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Suggestions for Further Study

• Can a stronger pump be used for force the
  solution through tinier micronozzles (ex 10 µm
  and 5 µm)?
• Is there a better way to increase yield of
  particles (particles stick to sides of, top of,
  and apparatus inside the collecting chamber and
  are hard to remove) and decrease amount lost to
  air?
• What would the results be if another
  supercritical fluid was used instead of CO2?
• Can the durability of the micronozzles be
  increased so they last more than one or two
  trials?