Superparamagnetism of ferrite particles dispersed in spherical polymeric materials

Superparamagnetic iron oxide particles synthesized in water-in-oil microemulsions have been incorporated into a polymer matrix. The microstructured micellar environment provides a template for polymer synthesis, leading to the formation of interconnected polymer particles with spherical morphologies. The resulting iron oxide-polymer composites reveal superparamagnetic properties and low temperature remanence and susceptibility characteristic of a superparamagnet. The results of temperature and field dependent magnetic characterizations of these composites are described. Ultramicrotomed TEM micrographs show that the iron oxide particles (size <100 /spl Aring/) are uniformly distributed In the polymer microspheres.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>