Photo-reactive Surfactant and Macromolecular Supramolecular Structures

dc.contributor.authorCashion, Matthew Paulen
dc.contributor.committeechairLong, Timothy E.en
dc.contributor.committeememberMoore, Robert Bowenen
dc.contributor.committeememberTurner, S. Richarden
dc.contributor.committeememberDavis, Richey M.en
dc.contributor.committeememberMadsen, Louis A.en
dc.description.abstractFor 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.degreePh. D.en
dc.publisherVirginia Techen
dc.rightsIn Copyrighten
dc.subjectgemini surfactantsen
dc.subjectn-butyl acrylateen
dc.subject2-hydroxyethyl acrylateen
dc.subjecthydrogen bondingen
dc.titlePhoto-reactive Surfactant and Macromolecular Supramolecular Structuresen
dc.typeDissertationen Polytechnic Institute and State Universityen D.en
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