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I. The use of ruthenium-based metathesis catalysts in the creation of two-dimensional and three-dimensional polymeric structures on silicon(100) surfaces and sol-gel glasses. II. The screening of peptide-based acyl transfer catalysts in a sensor-functi

Posted on:2004-02-28Degree:Ph.DType:Thesis
University:Boston CollegeCandidate:Harris, Robert Francis, IIIFull Text:PDF
GTID:2461390011962643Subject:Chemistry
Abstract/Summary:
Part I. The conventional fabrication of microfluidics usually involves 1–3 levels of processed silicon. Using current techniques to fabricate a system that requires a multi-level channel network, sensor array, or complex pumping system would be an arduous task. This thesis reports the development and implementation of methodology that would produce patterned polymers on a Si(100) oxide surface. A more advanced approach towards microstructure fabrication utilizing two-photon inactivation of a ring-opening metathesis polymerization (ROMP) catalyst bound inside the pores of a sol-gel monolith was subsequently developed.; The functionalization of SiO2 layers on Si(100) wafers with norbornyl trichlorosilane followed by introduction of a ruthenium-based carbene catalyst yields an immobilized active catalyst on the oxide surface. Subsequent exposure of the functionalized surface to monomer results in covalently attached polymer on the surface. The exposure of the functionalized surface to patterned UV light, followed by monomer exposure produces patterned polymers in high resolution as well as free-standing devices.; The adaptation of the surface functionalization methodology to 3-D glass supports (sol-gel) was straightforward. The use of two-photon microscopy to inactivate the catalyst below the surface of the support results in the formation of channels and structures in three dimensions. This research has laid the foundation for the creation of a new generation of polymer-based microelectrical-mechanical systems (MEMS).; Part II. Small peptides containing a nucleophillic N-alkylimidazole heterocycle as part of the π(Methyl)Histidine(Pmh) residue have been shown to be highly active for acyl transfer reaction involving alcohols and anhydrides. Potential catalyst candidates immobilized on resin beads were suspended in a polymeric gel that possessed a pH-sensitive fluorophore. The acidic by-products of the acyl transfer reaction produced fluorescent areas around beads with active catalysts. This change in fluorescence allowed for the rapid screening of acyl transfer catalysts.
Keywords/Search Tags:Acyl transfer, Catalyst, Surface, Sol-gel
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