Mechanics of emulsion droplets is crucial in applications where the encapsulated payload needs to be released under mechanical stimulus. This dissertation explores dumbbell nanoparticles as emulsifiers with focus on the emergent mechanical stability of the particle assembly at interfaces. Using a combination of freeze fracture shadow casting cryo-scanning electron microscopy and analytical modelling, I first investigate the complex adsorption behavior of individual dumbbells and discuss the corresponding implications for particle assembly at the interface. I then investigate the onset of mechanical instabilities in droplets stabilized by dumbbells using micropipette aspiration. I compare my findings to the control experiments of bare droplets and droplets stabilized with molecular surfactant under aspiration. In all three cases, the magnitude of the critical pressure for the onset of instabilities is set by the fluid surface tension. While particles have a dramatic impact on the mechanism of failure, the mechanical strength of the droplets is only modestly increased. This work provides experimental handles that can be tuned to aid the mechanical stability of emulsion droplets. The findings also inform advances in the mechanics of highly bendable sheets.
|Advisor:||Dufresne, Eric Robert|
|School Location:||United States -- Connecticut|
|Source:||DAI-B 78/11(E), Dissertation Abstracts International|
|Subjects:||Mechanics, Chemical engineering, Materials science|
|Keywords:||Assembly, Colloids, Interfaces, Mechanics, Nanoparticles, Soft Matter|
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