Tuesday, October 18, 2011
Exhibit Hall B (Minneapolis Convention Center)
Alkanethiol-stabilized gold nanoparticles (AuNPs) were deposited via a gas-expanded liquid (GXL) technique utilizing CO2-expanded hexane onto substrates of different surface energy. The different surface energies were achieved by coating silicon (100) substrates with various organic self-assembled monolayers (SAMs). Following the deposition of AuNP films, the films were characterized to determine the effect of substrate surface energy on nanoparticle film deposition and growth. Interestingly, the critical surface tension of a given substrate does not directly describe nanoparticle film morphology. However, the results in this study indicate a shift between layer-by-layer and island film growth based on the critical surface tension of the capping ligand. Additionally, the fraction of surface area covered by the AuNP film decreases as the oleophobic nature of the surfaces increases. Moreover, the influence of different capping ligands and the AuNP size and size distribution will also be discussed. On the basis of this information, the potential exists to engineer nanoparticle films with desired morphologies and characteristics.