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作者 Fenimore, Stephen G
書名 Interfacial self-assembly of sugar-based amphiphiles: Solid- and liquid-core capsules
國際標準書號 9781109552041
book jacket
說明 121 p
附註 Source: Dissertation Abstracts International, Volume: 71-01, Section: B, page: 0481
Adviser: Carlos C. Co
Thesis (Ph.D.)--University of Cincinnati, 2010
Sugar-swollen reverse micelles and alternating polymer vesicles were prepared to examine interfacial self-assembly of both small and macromolecular sugar-based amphiphiles. Anhydrous, glassy sugar-sucrose laurate mixtures spontaneously dissolve in hydrocarbon oil at moderate temperatures and form sugar-swollen reverse micelles. The size of the micelles and the microemulsion viscosity depend on the mass ratio of sugar to surfactant. As sugar loading increases, the micelles increase in size and bulk viscosity decreases. Formation of sugar-oil complex fluids is related to the dynamics of the sugar in the supercooled liquid state, investigated by modulated differential scanning calorimetry
Alternating polymers of N-n-alkylmaleimides and vinyl gluconamide spontaneously form ultra small (10 to 20 nm) and medium (50 to 300 nm) sized vesicles when dissolved in water at room temperature. These materials have molecular weights approximately one hundred times higher than alternating oligomers of alkylmaleate and vinyl ether monomers, and demonstrate conclusively that alternating copolymers can form vesicles. The size and shape of the vesicles are characterized thoroughly by cryogenic-transmission electron microscopy (cryo-TEM), dynamic light scattering (DLS), and small angle neutron scattering (SANS). The copolymer vesicles exhibit alkyl chain length dependent release characteristics and bilayer thickness (1.7, 2.0, and 2.6 nm for alkyl chains of 10, 12, and 14 carbons, respectively)
These nonionic alternating polymers contain no evident acidic or basic groups yet exhibit pH reversible self-assembly. The polymers form vesicles spontaneously in neutral, deionized water, precipitate under acidic conditions, and re-dissolve into optically clear, blue-tinted vesicular solutions upon neutralization of the turbid mixture. Cryo-TEM and DLS confirm that the size and structure of the vesicles remain the same after pH cycling. In the absence of ionic, acidic, and basic functionalities, the pH reversible self-assembly of this alternating polymer is likely driven by coordinated hydrogen bonding of protons within electron rich pockets of alternating vinyl gluconamide groups. This is consistent with measured titration curves and shifts in the infrared O-H stretch (3380 cm-1) of the gluconamide hydroxyl groups following acidification and neutralizing of the polymer in D2O
School code: 0045
Host Item Dissertation Abstracts International 71-01B
主題 Engineering, Chemical
0542
Alt Author University of Cincinnati. Chemical Engineering
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