NANOCUBE SYNTHESIS
AND DIMER
FORMATION
JASON MCHANN
2/05/2015
UNIVERSITY OF UTAH
THE END GOAL
REAL-TIME MOLECULAR
DETECTION
Gold nanocluster and pH indicator
(4-mercapto benzoic acid) Single
plasmonic na...
As a specific frequency of light is absorbed into the
resonance of plasmons, the transmitted and reflected
spectrum is alt...
ENHANCEMENT FACTOR
• Raman scattering a LOW probability
phenomena that is enhanced with
particle geometry.
• Geometry resu...
WHAT ARE NANO ANTENNA?
1. WHEN LIGHT INTERACTS WITH THE SURFACE OF A METAL, ITS ENERGY IS TRANSFERRED TO THE
FREE ELECTRON...
POLYPOL SYNTHESIS OF NANOCUBES
•
•
•
•
PVP
AgNC
PVP Monomer
111.139 g/mol
NANO CUBE SYNTHESIS
• Very straight forward reaction
with many sensitive variables.
REAGENTS
Ethylene Glycol: Heat to 150-160 c is necessary for equilibrium shift to favor formation of
acetaldehyde. Purity ...
•
•
•
•
2Cl / O
PUBLISHED DATA OF REAGENT VARIATION
E. V. Panfilova et al, “Study of polypol synthesis reaction parameters controlling hig...
Results of varying NaSH were inconclusive due to incorrect PVP concentration.
1.5mL 2/3/15
1.5mL 1/24/15
1.7mL 2/3/15 1.9m...
DIMERIZING
Hydrophobic Sonication
in Ethanol
1. PVP Ag Nanocubes
2. Deposition to substrate
3. Functionalize with
hydropho...
1) PDMS stamp hydrophobic octadecanethiol (ODT) on to top face of cube for 10
seconds.
2) Allow 5 minutes reaction time.
3...
POLY DIMETHYLSILOXANE - PDMS
• Biologically inert. Food additive.
• Resistant to polar solvents, swells with
non polar.
• ...
FUNNEL OF LOVE
1. Create a disperse monolayer at the
surface of a filled funnel.
2. Slowly drain fluid from funnel, thereb...
The current procedure is
extremely crude as a true
monolayer is not being formed
prior to stamping. Rather 3D
structures a...
NEXT…
•
•
•
THANK YOU
PROFESSOR MICHAEL HOEPFNER
& MICHAEL COTTAM
FUNCTIONALIZATION OF SILVER SURFACE
• Stabilizing PVP must be removed in order
to functionalize surface.
• Thiol-terminate...
of 20

nano cube syn and dimer

Published on: Mar 3, 2016
Source: www.slideshare.net


Transcripts - nano cube syn and dimer

  • 1. NANOCUBE SYNTHESIS AND DIMER FORMATION JASON MCHANN 2/05/2015 UNIVERSITY OF UTAH
  • 2. THE END GOAL REAL-TIME MOLECULAR DETECTION Gold nanocluster and pH indicator (4-mercapto benzoic acid) Single plasmonic nanoparticles for biosensing, Takumi et al. Functionalizing metallic nano structures with environmentally sensitive molecules allows for single molecule detection. Example: Disassociation of 4-MBA carboxyl group causes a shift in adsorbed spectra. Thus intracellular detection of pH gradients is possible.
  • 3. As a specific frequency of light is absorbed into the resonance of plasmons, the transmitted and reflected spectrum is altered. Ref: nanocomposix.com
  • 4. ENHANCEMENT FACTOR • Raman scattering a LOW probability phenomena that is enhanced with particle geometry. • Geometry results in hotspots in areas of small radius Rycenga et al.
  • 5. WHAT ARE NANO ANTENNA? 1. WHEN LIGHT INTERACTS WITH THE SURFACE OF A METAL, ITS ENERGY IS TRANSFERRED TO THE FREE ELECTRONS ON THE SURFACE. THESE FREE ELECTRONS COLLECTIVELY OSCILLATE AS A PLASMON 2. WHEN THE OSCILLATION IS RESTRICTED TO A DOMAIN COMPARABLE TO THE WAVELENGTH USED TO EXCITE IT, THEN IT IS A LOCALIZED SURFACE PLASMON(LSP). 3. THE ELECTRIC FIELD OF THE SURFACE IS GREATLY EFFECTED BY PLASMONS AND PROXIMITY TO OTHER OBJECTS CAN RESULT IN RESONANCE. 4. RESONANCE RESULTS IN ENHANCEMENT OF ELECTRIC FIELDS DUE TO GEOMETRY AND AREAS OF HEIGHTENED ELECTRIC FIELDS ARE KNOWN AS NANO ANTENNA. 5. RAMAN SCATTERING IS THEORIZED TO BE THE RESULT OF LIGHT INTERACTING WITH RESONATING PLASMONS TO EMIT RADIATION.
  • 6. POLYPOL SYNTHESIS OF NANOCUBES • • • • PVP AgNC PVP Monomer 111.139 g/mol
  • 7. NANO CUBE SYNTHESIS • Very straight forward reaction with many sensitive variables.
  • 8. REAGENTS Ethylene Glycol: Heat to 150-160 c is necessary for equilibrium shift to favor formation of acetaldehyde. Purity of low metallic ion concentration is important as it is competes with sulfur ions. Sodium Hydrosulfide: Initiator that dramatically decreases reaction time 10 fold. Acutually molar concentration is difficult to know because it is an unknown hydrate. Suggest moving to Sodium sulfide. Ratio of sodium sulfide to silver nitrate is 1:10,000.(Panfilova) PVP: Poly vinyl pyrrolidone. Regardless of molecular weight of polymer, it needs to exist in reaction in a ratio of 1:1.9-2.25 silver ions per repeating unit of PVP (C6H9NO). Silver Trifluoroacetate: Source of silver ions for reaction. Use of silver nitrate has been more widely used, but it is sensitive to heat. E. V. Panfilova et al, “Study of polypol synthesis reaction parameters controlling high yield of silver nanocubes.”
  • 9. •
  • 10. • • • 2Cl / O
  • 11. PUBLISHED DATA OF REAGENT VARIATION E. V. Panfilova et al, “Study of polypol synthesis reaction parameters controlling high yield of silver nanocubes.” 2006 Altering sodium sulfide from 26-32uM concentration in reaction vessle Altering Silver:PVP ratio (0.77, 1.155, 1.5, 2.3, .7)
  • 12. Results of varying NaSH were inconclusive due to incorrect PVP concentration. 1.5mL 2/3/15 1.5mL 1/24/15 1.7mL 2/3/15 1.9mL 2/3/15 1.25mL 1/24/15 Larger Size Distribution Rare cube formation Large Shape Distribution 35-45% Yield Notice over passivation decreases particle size
  • 13. DIMERIZING Hydrophobic Sonication in Ethanol 1. PVP Ag Nanocubes 2. Deposition to substrate 3. Functionalize with hydrophobic ligand 4. Release from substrate in ethanol 5. Wash and storage
  • 14. 1) PDMS stamp hydrophobic octadecanethiol (ODT) on to top face of cube for 10 seconds. 2) Allow 5 minutes reaction time. 3) Rinse with toluene(???) 4) Sonicate in hydrophilic 16-mercaptohexandecanoic acid (MHA) 5) Wash in ethanol.
  • 15. POLY DIMETHYLSILOXANE - PDMS • Biologically inert. Food additive. • Resistant to polar solvents, swells with non polar. • Two part polymer. • Elasticity can by tuned by mixing ratio. • Easy to make and inexpensive
  • 16. FUNNEL OF LOVE 1. Create a disperse monolayer at the surface of a filled funnel. 2. Slowly drain fluid from funnel, thereby reducing surface area. 3. Cubes should form compact monolayer.
  • 17. The current procedure is extremely crude as a true monolayer is not being formed prior to stamping. Rather 3D structures are dominating the surface preventing single face functionalization. More commonly we see this…
  • 18. NEXT… • • •
  • 19. THANK YOU PROFESSOR MICHAEL HOEPFNER & MICHAEL COTTAM
  • 20. FUNCTIONALIZATION OF SILVER SURFACE • Stabilizing PVP must be removed in order to functionalize surface. • Thiol-terminated molecules for a stronger covalent bond with silver than PVP and will irreversibly replace PVP. • If a specific percentage of replaced PVP is required, this can be accomplished by use of low thiol concentration and monitoring change in SERS spectrum.

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