The Role of Graphene Oxide - Polyacrylamide Interactions on the Stability and Microstructure of Oil-in-Water Emulsions
Date
2018-08
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Abstract
The emulsification of oil in water by nanoparticles (NPs) can be facilitated by addition of costabilizers, such as polymers and surfactants. However, the mechanism of this synergistic effect and its impacts on emulsions’ properties remain unclear. In my thesis project, I have studied the synergistic interaction of NP-polymer systems using graphene oxide (GO) and an anionic polyacrylamide (PAM) in stabilization of paraffin oil/water emulsion systems. Oil-free GO and GO-PAM dispersions were analyzed by imaging their morphology directly via Cryo-TEM and atomic force microscopy (AFM). X-ray diffraction (XRD) results confirm the adsorption of PAM molecules onto GO sheets resulting in the formation of ultimate GO-PAM complexes. The adsorption phenomenon is a consequence of hydrogen bonding and acid-base interactions, conceivably leading to a resilient hybrid electron-donor-acceptor complex. The microstructures of emulsions that are captured with two-color fluorescent microscopy and Cryo-TEM reveal the localization of GO-PAM complexes at the interface while large GO-PAM flocs coexist at the interface and in between oil droplets. Rheological measurements confirm that GO-PAM complexes have a higher desorption energy from the interface. Our findings, with insights into both structure and rheology, form a foundational understanding for integration of other polymers and NPs in emulsion systems, which enables efficient design of these systems for an application of interest.
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Keywords
Pickering emulsions, Graphene oxide, Graphene oxide - polyacrylamide
Citation
Jahandideh, H. (2018). The Role of Graphene Oxide - Polyacrylamide Interactions on the Stability and Microstructure of Oil-in-Water Emulsions (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/32879