title: Composite microdiscs with a magnetic belt: preparation, chaining properties, and use as switchable catalyst carriers.
abstract: We describe an emulsion-based preparation of patchy composite particles (diameter of 100-500 μm) consisting of a disclike epoxy core and a belt of porous polystyrene particles (diameter of 30 μm) with magnetite within the pores. Compared to the magnetically uniform polystyrene particles, the spontaneous aggregation of composite particles is suppressed when dispersed into liquid, which is attributed to the increased particle size, reduced magnetic susceptibility, and the shape of the magnetic domain distribution within the particles (spherical versus a belt). When the composite particles are coated by platinum-palladium layer we demonstrate they can be employed as switchable catalyst carriers, moving from one liquid phase to another when controlled by an external magnetic field.
authors: †Physics Department, Institute for Energy Technology, NO-2027 Kjeller, Norway.|‡Department of Physics, Technical University of Denmark, DK-2800 Kongens Lyngby, Denmark.
authors: Matti
authors: M
authors: Knaapila
authors: §GIAMAG Technologies AS, NO-2027 Kjeller, Norway.
authors: Henrik
authors: H
authors: Høyer
authors: †Physics Department, Institute for Energy Technology, NO-2027 Kjeller, Norway.|∥Department of Physics, University of Oslo, NO-0316 Oslo, Norway.
authors: Geir
authors: G
authors: Helgesen
keywords: active materials; anisotropy; catalyst; hybrid materials; magnetic particles; patchy particles