Suspensions of nanoparticles can act like solutions with thermally reversible, temperature dependent solubility [1].  Here we present solubility data for ca. 5.0 nm gold nanoparticles as a function of ligand shell, solvent [2] and temperature. The ligands were octane-, decane-, dodecane- and hexadecanethiols; the solvents were the n-alkanes from hexane to hexadecane and toluene. Supernatant concentrations in equilibrium with precipitated superclusters of nanoparticles were measured with UV-Vis spectrophotometry.  The solubility of nanoparticles ligated with decane- and dodecanethiol was greatest in n-decane and n-dodecane, respectively. In contrast, the solubility of nanoparticles ligated with octane- and hexadecanethiol showed decreasing solubility with increasing solvent chain length. In addition the solubility of the octanethiol ligated system showed a nonmonotonic solvent carbon number functionality with even numbered solvents being better solvents than neighboring odd numbered solvents. Solubilities increased with temperature, but showed extreme non-ideal behavior.[1] X.M. Lin, G.M. Wang, C.M. Sorensen, K.J. Klabunde, J. Phys. Chem. B103, 5488 (1999).[2] B. C. Lohman, J. A. Powell, S. Cingarapu, C. B. Aakeroy, A. Chakrabarti, K. J. Klabunde, B. M. Law, and C. M. Sorensen, Phys. Chem. Chem. Phys., 14, 6502- 6506 (2012).

Suspensions as solutions: Nanoparticle solubility as a function of solvent, ligand, and temperature

245th National Meeting (2013)

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