Novel Sputtered Stationary Phases for Solid Phase Microextraction, and Other Coatings and Materials for Surface Applications
The primary focus of my work has been to prepare new solid adsorbents for solid phase microextraction (SPME) via sputtering of silicon. The orientation of the silica substrates/fibers and the sputtering pressure induced the formation of porous and columnar structures. Sputtering was performed for di...
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ndltd-BGMYU2-oai-scholarsarchive.byu.edu-etd-72042019-05-16T03:32:04Z Novel Sputtered Stationary Phases for Solid Phase Microextraction, and Other Coatings and Materials for Surface Applications Diwan, Anubhav The primary focus of my work has been to prepare new solid adsorbents for solid phase microextraction (SPME) via sputtering of silicon. The orientation of the silica substrates/fibers and the sputtering pressure induced the formation of porous and columnar structures. Sputtering was performed for different times to yield fibers with different thicknesses. Piranha treatment of the surface increased the concentration of silanol groups, which underwent condensation with vapor deposited octadecyldimethylmonomethoxy silane to incorporate octadecyl chains onto the fiber surfaces. Silanized, sputtered fibers were preconditioned for 3 h at 320 °C to remove the unreacted chains. Comparison of the extraction efficiencies of 1.0 and 2.0 µm sputtered, silanized fibers with a commercial fiber (7 µm PDMS) for a series of analyte mixtures, which included alkanes, alcohols, aldehydes, esters, and amines, was demonstrated. The silanized, sputtered fiber performed better than the commercial fiber in extraction of most of the compounds. These fibers demonstrated long life as no degradation was seen even after 300 extractions. Carry-over between runs was not observed. The repeatability of the sputtered fibers was similar to commercial ones. The extraction of more than 50 compounds from a real world botanical sample using the 2.0 µm sputtered, silanized fiber was also demonstrated. In my second project, a facile method for the preparation of superhydrophobic surfaces (SHS) on glass and silicon surfaces was developed. A two-tier topography (needed for an SHS) was created in 60 min by the aggregation of nanosilica during in situ urea-formaldehyde polymerization. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) demonstrated rough topography. Vapor deposition of a low surface energy silane imparted hydrophobicity, which was confirmed by the presence of an F 1s signal in X-ray photoelectron spectroscopy (XPS). The prepared surfaces exhibited water contact angles (WCA) of greater than 150 °C with very low sliding angles. In my third project, a multilayer assembly of nitrilotris(methylene)triphosphonic acid, a corrosion inhibitor, and zirconium was constructed on alumina at room temperature. Attempts to prepare a layer-by-layer assembly at higher temperature (70 °C) was unsuccessful due to etching of the alumina surface. A suite of analytical techniques, XPS, AFM, time-of-flight secondary ion mass spectrometry, and spectroscopic ellipsometry was used to characterize these surfaces. This thesis also contains appendices of tutorial articles I wrote on modeling in ellipsometry, and data analysis tools (classical least squares and multivariate curve resolution). 2016-03-01T08:00:00Z text application/pdf https://scholarsarchive.byu.edu/etd/6204 https://scholarsarchive.byu.edu/cgi/viewcontent.cgi?article=7204&context=etd http://lib.byu.edu/about/copyright/ All Theses and Dissertations BYU ScholarsArchive Solid phase microextraction surface coatings superhydrophobic surface layer-by-layer Chemistry |
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Solid phase microextraction surface coatings superhydrophobic surface layer-by-layer Chemistry Diwan, Anubhav Novel Sputtered Stationary Phases for Solid Phase Microextraction, and Other Coatings and Materials for Surface Applications |
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The primary focus of my work has been to prepare new solid adsorbents for solid phase microextraction (SPME) via sputtering of silicon. The orientation of the silica substrates/fibers and the sputtering pressure induced the formation of porous and columnar structures. Sputtering was performed for different times to yield fibers with different thicknesses. Piranha treatment of the surface increased the concentration of silanol groups, which underwent condensation with vapor deposited octadecyldimethylmonomethoxy silane to incorporate octadecyl chains onto the fiber surfaces. Silanized, sputtered fibers were preconditioned for 3 h at 320 °C to remove the unreacted chains. Comparison of the extraction efficiencies of 1.0 and 2.0 µm sputtered, silanized fibers with a commercial fiber (7 µm PDMS) for a series of analyte mixtures, which included alkanes, alcohols, aldehydes, esters, and amines, was demonstrated. The silanized, sputtered fiber performed better than the commercial fiber in extraction of most of the compounds. These fibers demonstrated long life as no degradation was seen even after 300 extractions. Carry-over between runs was not observed. The repeatability of the sputtered fibers was similar to commercial ones. The extraction of more than 50 compounds from a real world botanical sample using the 2.0 µm sputtered, silanized fiber was also demonstrated. In my second project, a facile method for the preparation of superhydrophobic surfaces (SHS) on glass and silicon surfaces was developed. A two-tier topography (needed for an SHS) was created in 60 min by the aggregation of nanosilica during in situ urea-formaldehyde polymerization. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) demonstrated rough topography. Vapor deposition of a low surface energy silane imparted hydrophobicity, which was confirmed by the presence of an F 1s signal in X-ray photoelectron spectroscopy (XPS). The prepared surfaces exhibited water contact angles (WCA) of greater than 150 °C with very low sliding angles. In my third project, a multilayer assembly of nitrilotris(methylene)triphosphonic acid, a corrosion inhibitor, and zirconium was constructed on alumina at room temperature. Attempts to prepare a layer-by-layer assembly at higher temperature (70 °C) was unsuccessful due to etching of the alumina surface. A suite of analytical techniques, XPS, AFM, time-of-flight secondary ion mass spectrometry, and spectroscopic ellipsometry was used to characterize these surfaces. This thesis also contains appendices of tutorial articles I wrote on modeling in ellipsometry, and data analysis tools (classical least squares and multivariate curve resolution). |
author |
Diwan, Anubhav |
author_facet |
Diwan, Anubhav |
author_sort |
Diwan, Anubhav |
title |
Novel Sputtered Stationary Phases for Solid Phase Microextraction, and Other Coatings and Materials for Surface Applications |
title_short |
Novel Sputtered Stationary Phases for Solid Phase Microextraction, and Other Coatings and Materials for Surface Applications |
title_full |
Novel Sputtered Stationary Phases for Solid Phase Microextraction, and Other Coatings and Materials for Surface Applications |
title_fullStr |
Novel Sputtered Stationary Phases for Solid Phase Microextraction, and Other Coatings and Materials for Surface Applications |
title_full_unstemmed |
Novel Sputtered Stationary Phases for Solid Phase Microextraction, and Other Coatings and Materials for Surface Applications |
title_sort |
novel sputtered stationary phases for solid phase microextraction, and other coatings and materials for surface applications |
publisher |
BYU ScholarsArchive |
publishDate |
2016 |
url |
https://scholarsarchive.byu.edu/etd/6204 https://scholarsarchive.byu.edu/cgi/viewcontent.cgi?article=7204&context=etd |
work_keys_str_mv |
AT diwananubhav novelsputteredstationaryphasesforsolidphasemicroextractionandothercoatingsandmaterialsforsurfaceapplications |
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1719186834062311424 |