(691g) SANS and SAXS Study of Nanoparticle Adsorption At Oil-Water Interfaces

Nanoparticle-stabilized emulsions show various potential applications in the development of nanomaterials such as colloidosomes and composite particles. In this talk we will examine the adsorption of both charged nanoparticles and amphiphilic nanoparticle surfactants at dispersed oil-in-water emulsion interfaces. The adsorption of nanoparticles at emulsion interfaces has been typically difficult to study because of the wide range of size scales that are involved. Here, we show how Small Angle Neutron Scattering (SANS) and Small Angle X-ray Scattering (SAXS) can be used to quantitatively examine nanoparticle adsorption at dispersed oil-water interfaces directly and without any sample manipulation (e.g. drying). We have developed a detailed scattering model that makes it possible to quantitatively determine the fraction of an oil-water interface that is covered with adsorbed particles. From this model, we are able to systematically probe the influence of colloidal interactions on the adsorption of nanoparticles at these interfaces. Finally, we will also examine the emergence of new optical properties that result from collective plasmonic interactions in emulsion systems that are stabilized by metallic nanoparticles.