Phase transfer of surface-modified gold nanoparticles by hydrophobization with alkylamines

Abstract

The complete transfer from an aqueous to an organic solution of negatively charged carboxylate- and sulfonate-modified gold nanoparticles in the presence of primary amines is demonstrated. The transfer of carboxylate-modified gold nanoparticles to chloroform was found to be dependent on the pH of the aqueous phase. The sulfonate-modified gold nanoparticles readily transferred to chloroform in the presence of sodium chloride. Fourier transform infrared measurements showed that the transfer of particles occurred via acid-base pair formation between the carboxylate or sulfonate moieties on the nanoparticles and the protonated amine groups of the alkylamines. The transfer of the gold nanoparticl..