Solution Phase Behavior of Gold Nanoparticles in Colloidal Solution

Gold nanoparticles in colloidal solution can aggregate to form gold nanocrystal superlattices. To explore and understand the solution phase behavior of nanoparticles, the gold nanoparticles ligated with dodecanthiol in a mixture of 4-tert-butyltoluene and butanone were studied by UV-vis spectroscopy, static light scattering and dynamic light scattering. The results showed that there is a reversible dissolution-aggregation process. The phase diagram was obtained by measuring the size of the nanoparticles with dynamic light scattering and the scattered light intensity. The UV-vis spectroscopy also proved the existence of a phase transition.