Development and optimization of materials via nanoparticle modification and assembly

This thesis describes the development and optimization of materials using nanoparticles and self assembly techniques. Colloid self assembly and electroless metal deposition have been employed to fabricate substrates for surface enhanced Raman spectroscopy (SERS). The structure and stability of self assembly of mono- di- and tricarboxylic acid adsorbates on metal oxide nanoparticles has been explored. Finally, the use of a Au colloid monolayer as a template for replicating surface nanostructure has been investigated.; A novel combinatorial technique was developed to aid in the optimization of nanostructured materials. Ag-clad Au colloid particle arrays were fabricated using several different size Au colloid cores, and trends in SERS response as a function of nanostructure were mapped. The resulting libraries were characterized by uv-vis spectroscopy, atomic force microscopy (AFM), and field emission scanning electron microscopy (FE-SEM). Analysis suggests that particle coalescence is deleterious to the SERS response, even though the wavelength-dependant SERS enhancement is consistent with previous observations on roughened bulk substrates.; Chapters 4 and 5 explore the structure and binding stability of long chain alknaoic acids, and chelating organic acids on the surface of TiO ₂ and ZrO₂ nanoparticles. FT-IR spectroscopy confirms the crystalline-like structure of adsorbed long chain alkanoic acids, similar to the structure of adsorbed alkanethiols on Au, and pH titrations test the adsorption stability of the carboxylates. Long chain alkanes, but not shorter ones, form titration-stable nanoparticle coatings, as does the trifunctional adsorbate, Kemp's triacid. FT-IR spectroscopy and geometric models are used to comment on the configuration of the carboxylate-surface interaction, which appears to be the key to achieving titration-stable coatings of non-long chain alkane adsorbates.; Finally, chapter 6 explores the use of a Au colloid monolayer as a template for nanostructure replication. A colloid monolayer is encapsulated in a SiO ₂ sol-gel film, and then selective etching techniques are used to remove the Au colloids and leave behind the SiO₂ template. The process was monitored by uv-vis spectroscopy, AFM, and electrochemistry. Clear changes in film properties were observed at each step in the template fabrication process, indicating the feasibility of the strategy.