Synthesis And Magnetic Properties Of Block Copolymer-CoFe2O4 Nanoclusters

Abstract

The overall goal of this research is to explore techniques for the development of novel binary magnetic oxide nanoclusters uniformly distributed within a polymer matrix. These CoFe₂O₄ nanoclusters were synthesized at room temperature, and are confined within the self-assembled nanoscale structure exhibited by block copolymers templates. The diblock copolymers were synthesized by ring opening metathesis polymerization of norbornene and norbornene trimethylsilane and the binary magnetic oxide was introduced through a nanoreaction scheme using wet chemical methods. Transmission electron micrographs of microtomed thin sections of these nanocomposites show that the metal oxide nanoclusters are ellipsoidal in shape and are uniformly distributed within the polymer matrix. A SQUID magnetometer was used to study the magnetic properties of the polymeric nanocomposites at applied fields up to 5 Tesla and at a temperature range between 300 °K and 5 °K. Mössbauer spectroscopy was used to study the structure of the nanoconfined metal oxide, and confirmed the synthesis of CoFe₂O₄ nanoclusters exhibiting an inverse spinel structure. This study provided a better understanding of the nucleation, growth and distribution of metal oxide nanoclusters within block copolymers and indicated ways to control the magnetic properties of polymeric based nanocomposite materials. The development of such binary metal oxide - block copolymer nanocomposites is targeting the functionalization of such nanostructures into magnetic device technologies.