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

本项目涉及与纳米尺度磁性相关的两个研究领域：1。各种氧化铁相隔离在铁蛋白笼将被研究。储铁蛋白铁蛋白催化fe2 +可逆氧化为fe3 +，并催化后者水解聚合成直径约7 nm的铁矿物核，核表面的生长表现出自催化行为，加速了氧化和聚合反应。铁氧化酶中心位于蛋白质外壳上，在铁结合的初始阶段促进氧化。核心生长将在铁成核的初始阶段被阻止，以便检查从分子到颗粒行为的转变和表面催化活性的开始。电子和磁性能将被研究以阐明分子/固体边界和从氧化铁酶中心到核心表面催化活性的转换。对仿生材料开发和生物技术/制药应用感兴趣的磁铁蛋白也将进行研究。2. 双嵌段和/或三嵌段共聚物的微相分离为球形、圆柱形、片层状和核/壳结构，提供了定制尺寸和形状的磁性纳米结构的空间和电子限制。三嵌段共聚物纳米畴内的核/壳磁性纳米颗粒可以实现更高的矫顽力，从而成为下一代高密度磁存储介质。研究了氧化铁的磁性和电子性质以及嵌段共聚物的核壳纳米结构。短程磁序、内部自旋结构、自旋反转机制、矫顽力和有限粒径效应将在广泛的长度和时间尺度、温度和外磁场强度范围内进行研究。磁化测量，穆斯堡尔，铁磁共振和紫外-可见吸收研究将被使用。与材料性能、合成和加工参数的相关性将指导先进材料的合成策略开发。这是在研究和教育领域妇女专业机会（POWRE）计划下提供的一项研究加强补助金。该项目的职业相关目标是在维拉诺瓦大学（VU）开展实验凝聚态物理的综合研究和教育活动。由于麻省理工学院的弗朗西斯·比特国家磁铁实验室的关闭，她的职业生涯中断了一段时间，现在她正在恢复她在研究和教育方面的职业目标。在较早的时候，家庭责任阻碍了搬迁。她成功地建立了一个活跃的研究项目，让理工科本科专业的学生参与其中，这对将聘任从非终身制转变为终身制至关重要。在这个关键时刻，预计power的资助将对她作为研究人员和教育工作者的职业发展产生决定性影响。拟议的综合活动将推进磁性纳米晶格行为的基础知识，阐明铁蛋白的生物矿化作用，促进先进纳米复合材料的合成，增强VU的研究和教育基础设施，并促进PI的科学领导和职业目标，她目前是VU物理学唯一的女性教员。这项研究预计将在与磁性材料行为特别相关的基础水平上贡献基础材料科学知识，并协助研究和教育的整合。该项目由材料研究部和MPS OMA（多学科活动办公室）共同支持

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).***