The main focus of this thesis was to study the interfacial behaviour of natural surface-active components of bitumen, which are believed to be major contributors to water-in-oil emulsion stability. Langmuir and Langmuir-Blodgett (LB) films of Athabasca bitumen were studied using the Langmuir interfacial trough and Atomic Force Microscope (AFM).

To study the adsorption reversibility, multiple washing experiments with fresh toluene for bitumen, maltene, and asphaltene films at the toluene/ultrapure water interface and at the toluene/recycled process water interface were performed. Asphaltenes were found to be irreversibly adsorbed at the interface. Bitumen film exhibited similar to asphaltenes irreversible adsorption after it had been washed twice with toluene. For maltene films, consecutive washings showed a progressive loss of maltenes into washing toluene.

This thesis also investigated the influence of the nature of bulk oil and water phases on bitumen film interfacial properties. It was found that the compressibility of a bitumen film increases with increasing the content of toluene in the toluene-heptane mixture used as an oil phase or acetone in the toluene-acetone mixture used as a solvent phase. Addition of acetone or sodium naphthenate to the pure water phase was found also to increase the compressibility of bitumen films. It was demonstrated that at a high pH of the water phase and in the presence of calcium ions, or when the process water was used as a subphase, the bitumen film became more rigid.