Nanomaterials exhibit unique surface properties. Thus, there is a need to develop rigorous and detailed surface analysis methods for their characterization. The surface chemistries of carboxylic acid terminated self-assembled monolayers (COOH-SAMs) on Au nanoparticle (AuNP) surfaces were characterized with XPS.  As the AuNP diameter decreased and SAM chain length increased, the XPS atomic C/Au ratio on the surface increased. As the XPS C/Au atomic ratio depends on the SAM structure as well as the curved nature of the AuNPs, special XPS data analysis methods must be developed to accurately analyze SAM covered AuNPs. Simulated Electron Spectra for Surface Analysis (SESSA) was used for this purpose.   Quantities such as SAM density, thickness, surface roughness, etc. were tuned in SESSA to optimize agreement between simulated and experimental XPS compositions.  In addition to the COOH-SAMs, amine and ethylene glycol terminated SAMs on AuNPs were also characterized.

XPS characterization of functionalized gold nanoparticles

243rd National Meeting (2012)

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