Superparamagnetic nanocomposites based on poly(styrene-b-ethylene/butylene-b-styrene)/cobalt ferrite compositions |
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| Authors: | Guru S Rajan Stacy L Stromeyer Kenneth A Mauritz Guoxing Miao Prakash Mani Mohammad Shamsuzzoha David E Nikles Arunava Gupta |
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| Institution: | 1. School of Polymers and High Performance Materials, University of Southern Mississippi, Hattiesburg, MS 39406–0076, USA;2. Center for Materials for Information Technology, University of Alabama, Tuscaloosa, AL 35487, USA |
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| Abstract: | Magnetic nanoparticles were created in or around the sulfonated (s) polystyrene domains in a phase separated polystyrene-b-(ethylene-co-butylene)-b-styrene)] block copolymer (BCP) using an in situ inorganic precipitation procedure. The sBCP was neutralized with a mixed iron/cobalt chloride electrolyte and the doped samples were converted to their oxides by reaction with sodium hydroxide and further washing with water. Transmission electron microscopy indicated the presence of nanoparticles in the 5–25 nm size range. The metal oxide particle structures were studied using select area electron diffraction, which revealed that they are of the cobalt iron oxide composition (CoFe2O4). These nanocomposites were shown, using a superconducting quantum interference device magnetometer, to be superparamagnetic at 300 K and ferrimagnetic at 5 K. Nanocomposites consisting of smaller particles have a blocking temperature of 70 K, whereas it was 140 K for larger particles. |
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| Keywords: | Block copolymer templates In situ precipitation Cobalt iron oxide nanoparticles Superparamagnetism Morphology |
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