Whereas numerous studies of stabilization of nanoparticles (NPs) in electrolytes have examined biological fluids, the interest has grown recently in media with much higher ionic strengths including seawater and brines relevant to environmental science and subsurface oil and gas reservoirs. Both low molecular weight ligands and polyelectrolytes that are well solvated in concentrated salt solution have been grafted to iron oxide and silica particles to provide electrosteric stabilization. Spherical brushes of a fully dissociated polyanion, poly(AMPS), end-grafted to silica were colloidally stable up to 4.5M CaCl<sub>2 </sub>enabling the investigation of novel behavior in brush length. Furthermore, the stabilized particles interact weakly with silica and undergo low retention during transport in porous media.<br/>A variety of strategies will be presented to stabilize carbon dioxide/water foams with surfactants and/or nanoparticles, based on a mechanistic understanding of how the rheological properties are related to the foam texture and interfacial properties. For foams with ultra-low water contents, the large capillary pressure induces rapid drainage that destabilizes the aqueous lamellae between the gas bubbles. However, we show that these foams can be stabilized with a viscoelastic aqueous phase composed of entangled wormlike micelles.

Foams and dispersions at high salinity

254th National Meeting (2017)

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