The plasmonic properties of gold nanoparticles may have applications in detecting organic contaminants in freshwater. The sensing capabilities arise from the opto-electronic properties of plasmonic gold nanoparticles which result from light induced localized surface plasmon resonance (LSPR). Specific frequencies of light generate a strong oscillating electromagnetic field between nanoparticles. Thus, contaminants situated between gold nanoparticles can be detected using plasmonic sensing techniques. Our lab has developed a unique strategy to prepare 2-D arrays of gold nanoparticles by embedding them into bilayer peptoid nanosheets prepared at the oil-water interface. Previous experiments using surface functionalized gold nanoparticles with twelve carbon chained ligands have been able to create interparticle gaps of slightly different sizes (3nm - 9nm) depending on the nanoparticle concentration used in the synthesis. It is possible to functionalize gold nanoparticles of both varying hydrodynamic radii and ligand density. Thus, it may be possible to control the interparticle distance of the 5nm gold nanoparticles within the nanosheets by using AuNPs of varying ligand chemistries and density.
In this study, we explore the ligand exchange kinetics of gold nanoparticles functionalized with octanethiol. We expect that the octanethiol-functionalized nanoparticles with greater ligand densities will produce stable nanosheet structures with smaller inter-particle gaps between gold nanoparticles, which may make these sheets more effective sensors.