POWRE: Studies in Nanoscale Magnetism: Biomimetic Processes and Nanocomposite Materials Development

Villanova University, Villanova PA

Investigators

Abstract

This project addresses two areas of research relevant to nanoscale magnetism: 1. A variety of iron-oxide phases sequestered within apoferritin cages will be studied. The iron storage protein ferritin catalyzes the reversible oxidation of Fe 2+ to Fe 3+ and the hydrolytic polymerization of the latter into an iron mineral core of ca. 7-nm diam. The growing core surface exhibits self-catalytic behavior, accelerating the oxidation and polymerization reactions. A ferroxidase center on the protein shell facilitates oxidation at the initial stages of iron binding. Core growth will be arrested at the initial stages of iron nucleation in order to examine the transition from molecular to particle behavior of the growing core and onset of surface catalytic activity. The electronic and magnetic properties will be studied in order to elucidate the molecular/solid boundary and the switch from ferroxidase center to core surface catalytic activity. Magnetoferritins, of interest in biomimetic materials development and bio-technological/pharmaceutical applications, will also be studied. 2. Microphase separation of diblock and/or triblock copolymers into spherical, cylin-drical, lamellar and core/shell architectures affords the spatial and electronic confinement of magnetic nanostructures of tailored size and shape. Core/shell magnetic nanoparticles within tri-block copolymer nanodomains could achieve improved coercivities, leading to next generation high-density magnetic storage media. Magnetic and electronic properties of iron oxide and core/shell nanostructured morphologies within block copolymers will be characterized. Short-range magnetic order, internal spin structure, spin reversal mechanisms, coercivities and finite-particle-size effects will be studied over a wide range of length and time scales, temperature and external magnetic field strength. Magnetization measurements, Mossbauer, Ferromagnetic Reso-nance and UV-Vis absorption studies will be used. Correlation with materials properties, synthe-sis and processing parameters will guide synthetic strategies to advanced materials development. %%% This is a research enhancement grant made under the Professional Opportunities for Women in Research and Education (POWRE) program. The career related objective of this project is the initiation of an integrated research and education activity in experimental condensed matter physics at Villanova University (VU). The PI is resuming her career goals in research and educa-tion after an interruption in her career, due to the closing of the Francis Bitter National Magnet Laboratory at MIT. Family responsibilities precluded relocation at an earlier time. Her success in establishing an active research program, with the participation of undergraduate science majors, is crucial in turning an appointment from non-tenure to tenure track. POWRE funding, at this critical juncture, is expected to have a definitive impact on her career advancement as a re-searcher and educator. The proposed integrated activity will advance fundamental knowledge in the behavior of magnetic nanolattices, elucidate biomineralization in ferritin, facilitate the syn-thesis of advanced nanocomposite materials, enhance the infrastructure for research and educa-tion at VU and promote the scientific leadership and career objectives of the PI who is, presently, the only female faculty member in physics at VU. The research is expected to contribute basic materials science knowledge at a fundamental level of special relevance to the behavior of mag-netic materials, and to assist with the integration of research and education. The project is co-supported by the Division of Materials Research, and the MPS OMA(Office of Multidisciplinary Activities). ***