title: Oil-in-water emulsions stabilized by highly charged polyelectrolyte-grafted silica nanoparticles.
abstract: Fully sulfonated poly(styrenesulfonate) brushes were grown from the surface of colloidal silica particles and used to prepare stable trichloroethylene-in-water and heptane-in-water Pickering emulsions. These particles were highly charged and colloidally stable in water but could not be dispersed in trichloroethylene or heptane. Both two-phase (emulsion plus neat water) and three-phase (emulsion separating neat oil and water phases) systems were observed, with water-continuous emulsion phases in all cases. Emulsion phases containing as much as 83% (v/v) oil were stable for over six months. Poly(styrenesulfonate)-grafted particles were very efficient emulsifiers; stable emulsion phases were prepared when using as little as 0.04 wt% particles. The emulsifying effectiveness of the poly(styrenesulfonate)-grafted silica particles can be attributed to the hydrophobicity of the vinylic polymer backbone that makes this highly charged polyelectrolyte unusually surface active at the oil/water interface.
authors.affiliation: Department of Civil and Environmental Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213-3890, USA.
authors.forename: Navid
authors.initials: N
authors.lastname: Saleh
authors.forename: Traian
authors.initials: T
authors.lastname: Sarbu
authors.forename: Kevin
authors.initials: K
authors.lastname: Sirk
authors.forename: Gregory V
authors.initials: GV
authors.lastname: Lowry
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Matyjaszewski
authors.forename: Robert D
authors.initials: RD
authors.lastname: Tilton