Bituminous emulsions and their characterization by atomic force microscopy

Area of Science:

• Colloid and Surface Science
• Materials Science
• Nanotechnology

Background:

• Oil-in-water emulsions containing bitumen present challenges for characterization due to the dispersed phase.
• Understanding emulsion structure is crucial for applications in areas like petroleum recovery and environmental remediation.

Purpose of the Study:

• To introduce and validate a novel atomic force microscopy (AFM) method for high-resolution imaging of bitumen-in-water emulsions.
• To characterize the adsorption behavior, film formation, and surfactant localization of bitumen micelles on a substrate.

Main Methods:

• Utilized atomic force microscopy (AFM) with a liquid cell to image bitumen micelles adsorbed onto an atomically smooth mica substrate.
• Employed a continuous water phase with dispersed bitumen micelles for sample preparation.
• Measured the height of adsorbed bitumen films in both wet and dry states.

Main Results:

• Successfully visualized fine, polydispersed bitumen micelles adsorbed to the mica surface in solution.
• Quantified the height of the bitumen films, providing insights into their structure in different states.
• Determined the homogeneity of film formation resulting from micelle coalescence.
• Visualized the localization of surfactant molecules on and between the bitumen micelles.

Conclusions:

• The developed AFM method provides a powerful tool for detailed nanoscale observation of bitumen-in-water emulsions.
• The study elucidates the structural characteristics and film-forming properties of bitumen micelles.
• Insights into surfactant distribution offer a deeper understanding of emulsion stability and behavior.