Preparation and Electromagnetic\nProperties of Core/Shell\nPolystyrene@Polypyrrole@Nickel Composite Microspheres

Abstract

Through a novel method, we successfully synthesized electromagnetic\n(EM) functional polystyrene@polypyrrole@nickel (PS@PPy@Ni) composite\nmicrospheres. The PS@PPy spheres with well-defined core/shell structure\nhave been synthesized via an in situ chemical oxidative copolymerization\nof pyrrole (Py) and <i>N</i>-2-carboxyethylpyrrole (PyCOOH)\ntemplated by PS microspheres. The reaction was carried out under heterophase\nconditions using the mixture of ethanol and water as the continuous\nphase. Tailored by the carboxyl groups on the surface of microspheres,\nmagnetic nickel layer has been steady deposited onto the P­(Py-PyCOOH)\nlayer of the microspheres through an activation-electroless plating\ntechnology. The fine PS@P­(Py-PyCOOH)@Ni core/shell structures could\nbe obtained with the PyCOOH content up to 50 wt % in the P­(Py-PyCOOH)\nlayer. Moreover, the as-prepared PS@P­(Py-PyCOOH)@Ni composites are\nferromagnetic materials and behave as a good electromagnetic (EM)\nabsorption material due to the coating of Ni layer around the PS@P­(Py-PyCOOH)\nspheres. The PS@P­(Py-PyCOOH)@Ni composite spheres show the remarkable\nEM wave absorption property with the maximum reflection loss (around\n−20.06 dB) at 10.69 GHz. The EM wave absorption can retained\nlower than −10 dB within a broad frequency range from 9.16\nto 13.75 GHz.