Investigation on arrangement and fusion behaviors of gold nanoparticles at the air/water interface

The arrangement and fusion behavior of alkanethiol-stabilized gold nanoparticles were investigated at the air/water interface by the Langmuir–Blodgett (LB) method using two different organic solvent, toluene or hexane. The results showed that the organic solvent greatly affected the arrangement and fusion behavior of the gold particles. In the case of toluene solvent, alkyl chains of alkanethiol combined to gold particles spread out, and the diameter of the gold particles became almost equal with each other, resulting in the spontaneous ordered arrangement in closed packed array by self-organization. The fusion of particles was clearly confirmed from the lattice image of the fused particles observed by high-resolution transmission electron microscopy (TEM). The difference in the arrangement and fusion of the nanoparticles caused by the organic solvent was a result of the different affinity of the organic solvent with the alkyl chain of alkanethiol, which can be predicted using the solubility parameter.