(439c) Random Sequential Adsorption of Hydrophobic Gold Nanoparticle Monolayers Using Charged Surfactants

Charge transport in assemblies of metallic and semiconducting nanoparticles is of great interest for a wide range of applications including thin-film transistors, conductive composites, batteries, capacitors, thermoelectric and photonic devices. Gold nanoparticles are widely studied in order to understand these transport processes due to their simple synthesis, facile surface modification, and interesting optical properties. A major challenge in studying charge transport in gold nanoparticle assemblies is controlling the interparticle spacing and their arrangement. One promising strategy for creating gold nanoparticle thin films with controlled morphology is the use of Random Sequential Adsorption (RSA). RSA is a process where particles are randomly introduced in a system, and if they do not overlap any previously adsorbed particle, they adsorb and remain fixed for the rest of the process. In this work, we explore the RSA of gold nanoparticles using an innovative surfactant templating strategy that provides independent control of the microstructure of the produced thin films through the surfactant concentration. We use UV-Vis spectroscopy, dynamic light scattering and zeta-potential measurements to characterize stability and microstructure of functionalized gold nanoparticles in suspension as a function of salt concentration and surfactant concentration. Furthermore, we explore monolayer formation on oppositely charged substrates exposed to these coating solutions using Transmission Electron Microscopy (TEM) and Atomic Force Microscopy (AFM). Our results provide evidence for cooperative adsorption of functionalized nanoparticles that produce monolayer and clustered particle morphologies.