Measuring the Solubility of Ligated Gold Nanoparticles in Hydrocarbon Solvents

By Jeffrey Powell

Physics REU Summer 2009

Partially Funded Through NSF

Nanotechnology

Reside at the edge of quantum mechanics and condensed matter

Can act and behave as a “supermolecule”

Large ratio of surface area to volume Tip of the Iceberg

Synthesis of Gold Nanoparticles

Inverse Micelle Method-Soaps and Salts Reduction of Gold Salt to grow

nanocrystals Ligands added to stabilize Micellar Diffusion structures nanocrystals

Digestive Ripening

Reflux solution of polydisperse particles

Forms monodisperse solution

Post Digestive RipeningPre Digestive

Ripening

Alkane Ligated Gold Particle

Au

Au3850(C12SH)350

Solubility Tests

Dissolved in alkane solvents Centrifuge at 12000g acceleration Take UV-Vis absorbance data on the

supernatant Raw data converted into concentration of

gold in solution

Data

Data

“Like Dissolves Like”

Thiol chain length influences

solubility

Gold concentration peaks where

solvent similar to ligand

Data

Data

“Like Does Not ALWAYS Dissolve Like”

Peaks not where expected

Unknown forces at work

Struggles

Separation of two-phase system

Melting point of hexadecane thiol

Stability of particles

Conclusion

Suspension of particles acting as a

thermal reversible solution

Future Work