title: Double-phase-functionalized magnetic Janus polymer microparticles containing TiO2 and Fe2O3 nanoparticles encapsulated in mussel-inspired amphiphilic polymers.
abstract: Recently, anisotropic colloidal polymeric materials including Janus microparticles, which have two distinct aspects on their surfaces or interiors, have garnered much interest due to their anisotropic alignment and rotational orientation with respect to external electric or magnetic fields. Janus microparticles are also good candidates for pigments in "twisting ball type" electronic paper, which is considered promising for next-generation flexible display devices. We demonstrate here a universal strategy to encapsulate inorganic nanoparticles and to introduce different such inorganic nanoparticles into distinct polymer phases in Janus microparticles. TiO2 and Fe2O3 nanoparticles were separately encapsulated in two different mussel-inspired amphiphilic copolymers, and then organic-inorganic composite Janus microparticles were prepared by simple evaporation of solvent from the dispersion containing the polymer and nanoparticle. These Janus microparticles were observed to rotate quickly in response to applied magnetic fields.
authors.affiliation: Institute of Multidisciplinary Research for Advanced Materials (IMRAM), Tohoku University , 2-1-1 Katahira, Aoba-Ku, Sendai, To̅hoku, 980-8577, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Yabu
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Ohshima
authors.forename: Yuta
authors.initials: Y
authors.lastname: Saito
mesh_terms: D000818:Animals; D049872:Bivalvia / Q000737:chemistry*; D003911:Dextrans / Q000737:chemistry*; D008027:Light; D060526:Magnetic Fields; D060328:Magnetic Phenomena; D058185:Magnetite Nanoparticles / Q000737:chemistry*; D053758:Nanoparticles / Q000737:chemistry / Q000648:ultrastructure; D011108:Polymers / Q000737:chemistry*; D012542:Scattering, Radiation; D013052:Spectrometry, X-Ray Emission; D017550:Spectroscopy, Fourier Transform Infrared; D013501:Surface-Active Agents / Q000737:chemistry*; D014025:Titanium / Q000737:chemistry*
chemical_list: D003911:Dextrans; D058185:Magnetite Nanoparticles; D011108:Polymers; D013501:Surface-Active Agents; C009495:titanium dioxide; D014025:Titanium; C065507:ferumoxides
keywords: Janus particles; amphiphilic polymers; inorganic nanoparticles; mussel-inspired; phase separation