(750f) Surfactant-Mineral Interactions with Applications in Oil-Spill Dispersion and Clean-up

We consider silica nanoparticles in terms of their ability to disperse oil in water.  The surface properties of silica are modified by a change in the solution pH and/or the adsorption on the surface of surfactants of the poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) family.  The physical adsorption of surfactant polymers, and corresponding interactions between silica nanoparticles, can be modulated by the addition of displacers such as polar organic solvents, PEO homopolymers, or electrolytes.  The connection that we establish between (a) the surfactant organization on the nanoparticle surface and in the bulk solution and (b) macroscopic properties of the dispersions can guide the design of oil-in-water dispersants that incorporate environmentally benign nanoparticles.