Photo-reactive Surfactant and Macromolecular Supramolecular Structures
dc.contributor.author | Cashion, Matthew Paul | en |
dc.contributor.committeechair | Long, Timothy E. | en |
dc.contributor.committeemember | Moore, Robert Bowen | en |
dc.contributor.committeemember | Turner, S. Richard | en |
dc.contributor.committeemember | Davis, Richey M. | en |
dc.contributor.committeemember | Madsen, Louis A. | en |
dc.contributor.department | Chemistry | en |
dc.date.accessioned | 2014-03-14T20:12:03Z | en |
dc.date.adate | 2009-06-11 | en |
dc.date.available | 2014-03-14T20:12:03Z | en |
dc.date.issued | 2009-04-30 | en |
dc.date.rdate | 2012-03-30 | en |
dc.date.sdate | 2009-05-14 | en |
dc.description.abstract | For the first time nonwoven fibrous scaffolds were electrospun from a low molar mass gemini ammonium surfactant, N,N–-didodecyl-N,N,N–,N–-tetramethyl-N,N–-ethanediyl-di-ammonium dibromide (12-2-12). Cryogenic transmission electron microscopy (cryo-TEM) and solution rheological experiments revealed micellar morphological transitions of 12-2-12 in water and water:methanol (1:1 vol). Electrospinning efforts of 12-2-12 from water did not produce fibers at any concentration, however, electrospinning 12-2-12 in water:methanol at concentrations greater than 2C* produced, hydrophilic continuous fibers with diameters between 0.9 and 7 μM. Photo-reactive surfactants were synthesized to electrospin robust surfactant membranes. Before electrospinning it was important to fundamentally understand the structure-property relationship of gemini surfactants. The thermal and solution properties were explored for a series of ammonium gemini surfactants using differential scanning calorimetry (DSC), polarized light microscopy (PLM), and conductivity experiments. The Kraft temperature (Tk) was measured in water and water:methanol (1:1 vol) to investigate the influence of solvent on the surfactant solution properties. Other experiments investigate how associated photo-curable architectures are applicable in macromolecular architectures, to gain a fundamental understanding of how hydrogen bonding associations influence the photo-reactivity of functionalized acrylic copolymers. Novel hot melt pressure sensitive adhesives (HMPSAs) were developed from acrylic terpolymers of 2-ethylhexyl acrylate (EHA), 2-hydroxyethyl acrylate (HEA), and methyl acrylate (MA) functionalized with hydrogen bonding and photo-reactive functionalities. The synergy of hydrogen bonding and photo-reactivity resulted in higher peel values and rates of cinnamate photo-reactivity with increasing urethane concentration. Random copolymers of poly(n-butyl acrylate (nBA)-co-2-hydroxyethyl methacrylate (HEMA)) were functionalized with hydrogen bonding and photo-reactive groups to explore the photo-curing of associated macromolecular architectures. The influence of urethane hydrogen bonding on the photo-reactivity of cinnamate-functionalized acrylics was investigated with photo-rheology and UV-vis spectroscopy. Cinnamate-functionalized samples displayed an increase in modulus with exposure time, and the percentage increase in modulus decreased as the urethane content increased. The synergy of hydrogen bonding and photo-reactive groups resulted in higher rates of cinnamate photo-reactivity with increasing urethane concentration. Electrospun fibers were in situ photo-crosslinked to develop fibrous membranes from cinnamate functionalized low Tg acrylics. Electrospinning was conducted approximately 55 °C above the Tg of the cinnamate acrylate and the electrospun fibers did not retain their fibrous morphology without photo-curing. However, electrospun fibers were collected that retained their fibrous morphology and resisted flow when in situ photo-cured during electrospinning. The intermolecular photo-dimerization of cinnamates resulted in a network formation that prevented the low Tg cinnamate acrylate from flowing. | en |
dc.description.degree | Ph. D. | en |
dc.identifier.other | etd-05142009-143351 | en |
dc.identifier.sourceurl | http://scholar.lib.vt.edu/theses/available/etd-05142009-143351/ | en |
dc.identifier.uri | http://hdl.handle.net/10919/27714 | en |
dc.publisher | Virginia Tech | en |
dc.relation.haspart | MatthewCashionDissertation.pdf | en |
dc.rights | In Copyright | en |
dc.rights.uri | http://rightsstatements.org/vocab/InC/1.0/ | en |
dc.subject | photo-curing | en |
dc.subject | gemini surfactants | en |
dc.subject | n-butyl acrylate | en |
dc.subject | 2-hydroxyethyl acrylate | en |
dc.subject | cinnamate | en |
dc.subject | hydrogen bonding | en |
dc.subject | adhesives | en |
dc.subject | electrospinning | en |
dc.subject | photo-rheology | en |
dc.title | Photo-reactive Surfactant and Macromolecular Supramolecular Structures | en |
dc.type | Dissertation | en |
thesis.degree.discipline | Chemistry | en |
thesis.degree.grantor | Virginia Polytechnic Institute and State University | en |
thesis.degree.level | doctoral | en |
thesis.degree.name | Ph. D. | en |
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