title: Silicone oil emulsions stabilized by semi-solid nanostructures entrapped at the interface.
abstract: Oil-in-water (O/W) emulsions are typically stabilized using water-soluble surfactants, which anchor to the surface of oil droplets dispersed in an aqueous solution. The structure of the anchored surfactants is often susceptible to physical and chemical stresses because of their highly mobile properties. Here we introduce a new approach to prepare stable silicone oil emulsions under various external stresses using a water-insoluble amphiphilic block copolymer, poly(ethylene oxide)-b-poly(epsilon-caprolactone) (PEO-b-PCL). Above the melting temperature (around 60 degrees C) of the hydrophobic segment (PCL), PEO-b-PCL can be dissolved in silicone oil. When the polymer/oil mixture is dispersed in water, PEO-b-PCL is irreversibly reorganized into solid nanostructures at the interface of the aqueous/organic phases. The resulting interfacial structures provide a robust physical barrier to the emulsion coarsening processes. Accordingly, the prepared emulsions exhibit excellent structural tolerance against external stresses, including variations in pH, ionic strength, and temperature.
authors.affiliation: Amore Pacific R&D Center, 314-1 Bora-dong Giheung-gu Yongin-si, Gyounggi-do 449-729, Republic of Korea. yoonsung@mit.edu
authors.forename: Yoon Sung
authors.initials: YS
authors.lastname: Nam
authors.forename: Jin-Woong
authors.initials: JW
authors.lastname: Kim
authors.forename: Jongwon
authors.initials: J
authors.lastname: Shim
authors.forename: Sang Hoon
authors.initials: SH
authors.lastname: Han
authors.forename: Han Kon
authors.initials: HK
authors.lastname: Kim
mesh_terms: D004655:Emulsions / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D007783:Lactones / Q000737:chemistry*; D049329:Nanostructures / Q000737:chemistry*; D009994:Osmolar Concentration; D010316:Particle Size; D011092:Polyethylene Glycols / Q000737:chemistry*; D012827:Silicone Oils / Q000737:chemistry*; D013499:Surface Properties; D013501:Surface-Active Agents / Q000737:chemistry*; D013696:Temperature; D014867:Water / Q000737:chemistry
chemical_list: D004655:Emulsions; D007783:Lactones; D012827:Silicone Oils; D013501:Surface-Active Agents; C473831:poly(ethylene oxide)-b-poly(caprolactone); D014867:Water; D011092:Polyethylene Glycols