Asphaltenes, maltenes and silica nanoparticles at air-water and toluene-water interfaces.

摘要

In this thesis, deasphalted bitumen (maltenes) and asphaltenes extracted from Athabasca oil sands bitumen, and fumed silica nanoparticles were studied at air-water and toluene-water interfaces. Interfacial behaviours of individual components and their mixtures were characterized with pressure-area isotherms obtained with a Langmuir trough. Single layer Langmuir-Blodgett films were deposited onto silicon wafers and examined with an atomic force microscope and scanning electron microscope.; At the air-water interface, similarities in the pressure-area isotherms of the asphaltene and silica films were observed. Langmuir films of asphaltenes or silica mixed with maltenes showed similar phase transitions. Silica particles were aggregated into clusters at the interface, and when maltenes and asphaltenes are present with silica the size of the clusters is reduced.; At the toluene-water interface, maltenes form a compressible film and most of the maltenes dissolve into the toluene. Observed interfacial characteristics of asphaltenes and silica support their role as emulsion stabilizers.