Single-Nanoparticle Electrochemical Collision for Monitoring Self-Assembly of Thiol Molecules on Au Nanoparticles.

A precise understanding of the self-assembly kinetics of small molecules on nanoparticles (NPs) can give greater control over the size and architecture of the functionalized NPs. Herein, a single-nanoparticle electrochemical collision (SNEC)-based method was developed to monitor the self-assembly processes of 6-mercapto-1-hexanol (6-MCH) and 1-hexanethiol (MCH) on Au NPs at the single-particle level, and to investigate the self-assembly kinetics exactly. Results showed that the self-assembly processes of both consisted of rapid adsorption and slow recombination. However, the adsorption rate of MCH was significantly lower than that of 6-MCH due to the poorer polarity. Also noteworthy is that the rapid adsorption of 6-MCH on Au NPs conformed to the Langmuir model of diffusion control. Hence, the proposed SNEC-based method could serve as a complementary method to research the self-assembly mechanism of functionalized NPs.