title: In Situ Assembly of Hydrophilic and Hydrophobic Nanoparticles at Oil-Water Interfaces as a Versatile Strategy To Form Stable Emulsions.
abstract: We report a conceptually new strategy for forming particle-stabilized emulsions. We begin with stable, dilute suspensions of highly hydrophilic nanoparticles in water and hydrophobic nanoparticles in oil. When the two suspensions are mixed, attractive interactions between the hydrophilic and hydrophobic particles cause them to assemble at the oil-water interfaces into partially wettable or Janus-like clusters that effectively stabilize emulsions. By tuning the ratio of hydrophilic to hydrophobic particles in the clusters, both water-in-oil as well as oil-in-water emulsions can be formed. The van der Waals interaction energy between two particle types across an aqueous-organic interface provide a systematic guide to particle and liquid combinations that can form stable emulsions using our strategy, or identify when emulsions will not form. Our experiments and analysis provide a new platform for the formation of particle-stabilized emulsions and can be used to combine particles of different functionalities at emulsion droplet surfaces for generating novel materials.
authors.affiliation: Department of Chemical Engineering, University of Rhode Island , Kingston, Rhode Island 02881, United States.
authors.forename: Amitesh
authors.initials: A
authors.lastname: Saha
authors.affiliation: Department of Chemical and Biomolecular Engineering, Tulane University , New Orleans, Louisiana 70118, United States.
authors.forename: Vijay T
authors.initials: VT
authors.lastname: John
authors.affiliation: Department of Chemical Engineering, University of Rhode Island , Kingston, Rhode Island 02881, United States.
authors.forename: Arijit
authors.initials: A
authors.lastname: Bose
keywords: in situ particle cluster assembly; particle aggregates; particle-stabilized emulsion; van der Waals interaction