High pressure nuclear magnetic resonance studies of self-assembly structures formed with phosphorous fluorosurfactants in liquid/supercritical carbon dioxide.

摘要

A high pressure sample delivery and mixing setup was developed for in situ Nuclear Magnetic Resonance (NMR) measurements of water-in-carbon dioxide (W/C) microemulsions formed with home synthesized phosphorous fluorosurfactants in liquid and supercritical carbon dioxide (CO2). Relaxation and diffusion measurements were performed on the systems formed with those surfactants with different counter ions. Interfacial tension (IFT) and Small Angle Neutron Scattering (SANS) measurements were done for the purpose of comparison with the results obtained from NMR measurements.; Chapter I presents the introductory and background information about this project, including the CO2 properties, microemulsion formation and application, and the principles of Pulsed Field Gradient (PFG) NMR. In chapter II the development of a high pressure sample delivery and mixing setup is introduced, as well as the fabrication of high pressure NMR cells.; Chapter III covers the diffusion measurements of water dissolved in CO 2 continuous phase at various temperatures and pressures, as the preliminary experimental results for the explanation of phenomena observed in later chapter IV. Relaxation and diffusion measurements of components in W/C microemulsions formed with bis[2(F-hexyl)ethyl] (DiFg) phosphorous fluorosurfactant series with different counter ions (including Na+, NH4 + and N(CH3)4+) are discussed in chapter IV. The IFT measurement results are also introduced in this chapter. In chapter V SANS experiments on the WIC microemulsion system formed with NH4+-DiF8 are presented. The results obtained from SANS data simulation are compared with the results from the PFG NMR method. With an appropriate correction results from these two different techniques are consistent.; The last chapter summarizes the research project and presents a discussion of potential future study.