Announcing the Final Examination of Mr. Pooria Golvari for the degree of Doctor of Philosophy
Surface modification of colloidal nanoparticles is essential for broadening the scope of nanotechnology. In this dissertation, we discuss novel approaches to functionalize the surface of nanoparticles to tailor their properties for applications including radical polymerization inhibitors, supported heterogeneous catalysts, and building blocks for plasmonic devices. In the first chapter, we investigate the interaction of hydrogen-terminated silicon nanoparticles (H-SiNPs) with Karstedt’s catalyst and report a room‑temperature synthesis of Pt-coated SiNPs with highly tunable Pt loading. Analysis of the Pt on-Si ensemble reveals surface-bound Pt(II) on SiNPs which can undergo ligand exchange. Upon calcination, Pt-loaded SiNPs catalyze the hydrogenation of phenyl acetylene, and the SiNP scaffold enables efficient recovery and reuse of the catalyst. Conditions that favor the reductive elimination of the catalyst and efficient hydrosilylation of olefins are also discussed. In the second chapter, we report H-SiNPs as inhibitors for anerobic thermal autopolymerization of methacrylates. Prior to use, these solid-state inhibitors can be easily removed from the methacrylic monomers by low-speed centrifugation, offering great advantage to the traditionally used phenols and quinones. Analysis of SiNPs isolated after heating in methacrylates reveals the grafting of ester groups. As such, thermal hydrosilylation is presented as a powerful yet facile route to attach ester and allyl ester groups onto the surface of SiNPs. Finally, we report novel processes for controlled cluster formation and selective deposition of ligand-capped gold nanoparticles (AuNPs) in arrays of host nanoholes. Periodic assemblies of plasmonic nanoparticles are attractive as tunable substrates for surface-enhanced Raman spectroscopy, as well as analyte sensors based on coupled localized surface plasmon resonance and diffractively coupled plasmonic surface lattice resonances. Our processes are based upon lithographic patterning of substrates and subsequent deposition of AuNPs and provide a means for independently controlling properties of plasmonic nanoparticles and clusters, and those of the host lattice.
Committee in Charge:
Dr. Stephen M. Kuebler (chair)
Dr. Lei Zhai
Dr. Fernando Uribe-Romo
Dr. Titel Jurca
Dr. Xiaoming Yu