Magnetic Oxide Nanoparticles Templated By the Self-Assembly of Block Copolymers

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CTS-0347319P. Kofinas, University of Maryland College ParkThe purpose of this renewal proposal to a previously obtained CAREER award, is to incorporate half metallic nanoparticles into the self-assembled domains of microphase separated diblock copolymers and to synthesis spherical and cylindrical functional nanostructures exhibiting improved magnetic properties. Ring-opening metathesis polymerization (ROMP) of norbornene and its derivatives has proved to be a very effective way of synthesizing metal-functionalized block copolymers of narrow polydispersity. The block copolymer microphase separation can be effectively used as a template to confine nanoparticles of inorganic materials within one of the nanodomains. The self-assembled nature of the domain structure in block copolymers allows control over the shape and size and dispersion of 10-500 angstrom nanoparticles.We plan to carefully synthesize specific families of polymer templated nanocomposite compounds in bulk and thin-film form under controlled conditions, establish their structure, chemical stoichiometry, and degree of order, and then correlate the magnetic properties with the structural-chemical parameters. A unique combination of conventional and magnetic neutron scattering will be used to establish the relationship between the polymer self-assembly and the magnetic properties will be conducted for a broad class of ferromagnets that will be incorporated into the self-assembled polymer nanodomains including known half-metallic systems such as CrO2, spinels such as NiFe2O4 and layered ferrites such as Ba2Fe6O19.The broader impacts of the proposed research relate to magnetism in nanometer systems, a fascinating topic in fundamental science, which is also closely related to the advancement of the state-of-the-art technologies in microelectronics since magnets are vital components of electronic devices. As the dimension of microelectronic system continually shrinks and demands for small-dimension components increase, the understanding and controlling magnetic properties of small length scale magnets such as nanoparticles becomes increasingly crucial. Nanocrystalline oxide spinels are of interest both for fundamental studies in magnetic properties that have found numerous applications in high frequency devices, memory cores and magnetic recording media.The pursuit of this research will result in training of a new generation of undergraduate and graduate students and build research infrastructure in an area of vital importance to future technical developments in the polymer and microelectronic industries. The education activities to be undertaken include undergraduate and graduate teaching, graduate student advising, and various opportunities in undergraduate research involvement and mentoring, as well as the development of an interactive web page. Middle school teachers and students will also be exposed to aspects of nanoparticle research through RET and REU supplements, which will be requested if this proposal is funded.