Nanoparticle Transport and Interfacial Behavior in EP Operations

Nanoparticles have been shown to be outstanding interfacial agents and in particular nanoparticles have been shown to drive the interfacial tension between oil and water to values below 15 mN/m at concentrations of the order of a few ppm. We have developed a comprehensive program to examine and understand the ability of nanoparticles to act as interfacial agent. Specifically, we have attempted to understand the role of particle chemistry (metal, metal oxide, inorganic, carbon) along with surface functionalization chemistry and that of the particle size and to a limited extent shape on the interfacial tension reduction achieved by such nanoparticles. Additionally, to understand the origins of these interfacial properties we are also using grazing incidence x-ray scattering from oil (alkane) water interfaces with particles with tailored surface properties to examine the interfacial structuring of the particles. Recent studies using “Janus” spherical gold nanoparticles (diameter 10 nm) with a hydrophobic polymer on one side and a hydrophilic polymer on the other have shown a significant enrichment of the surface concentration with the incipient formation of hexagonally ordered domains at the surface coinciding with the saturation of the interfacial tension reduction caused by the particles.