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

POWRE：纳米磁性研究：仿生过程和纳米复合材料开发

• 批准号: 0074537
• 负责人: Georgia Papaefthymiou
• 金额: $ 7.5万
• 依托单位: Villanova University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-06-01 至 2002-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0074537&HistoricalAwards=false
• 关键词: POWRE; Studies; Nanoscale; Magnetism; Biomimetic

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).***

本计画针对奈米尺度磁性相关的两个研究领域：1。各种铁氧化物相隔离内脱铁铁蛋白笼将进行研究。铁储存蛋白铁蛋白催化Fe 2+可逆氧化为Fe 3+，并催化后者水解聚合成约100 μ m的铁矿物核。直径7 nm生长的核表面表现出自催化行为，加速氧化和聚合反应。蛋白质壳上的铁氧化酶中心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，以检查从分子到颗粒行为的增长的核心和表面催化活性的开始的过渡。电子和磁性的性质将进行研究，以阐明分子/固体边界和开关从铁氧化酶中心的核心表面催化活性。磁铁蛋白，在仿生材料开发和生物技术/制药应用的兴趣，也将进行研究。2.将二嵌段和/或三嵌段共聚物微相分离成球形、圆柱形、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改善的磁性，从而导致下一代高密度磁存储介质。铁氧化物的磁性和电子性能和核/壳纳米结构的形态嵌段共聚物内的特点。短程磁序，内部自旋结构，自旋反转机制，磁率和有限颗粒尺寸的影响将在很宽的范围内的长度和时间尺度，温度和外部磁场强度进行研究。将使用磁化测量、穆斯堡尔谱、铁磁共振和紫外-可见吸收研究。与材料性能、合成和工艺参数的相关性将指导先进材料的合成策略。这是根据研究和教育领域妇女专业机会方案提供的一项研究增强补助金。该项目的职业相关目标是在维拉诺瓦大学（VU）实验凝聚态物理学的综合研究和教育活动的启动。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，PI在职业生涯中断后，重新开始了她在研究和教育方面的职业目标。家庭责任使他们不能在较早的时候搬迁。她成功地建立了一个积极的研究计划，与本科科学专业的参与，是在把任命从非终身职位到终身职位的轨道至关重要。在这个关键时刻，POWRE的资金预计将对她作为一名教师和教育工作者的职业发展产生决定性的影响。拟议的综合活动将推进磁性纳米晶格行为的基础知识，阐明铁蛋白中的生物矿化，促进先进纳米复合材料的合成，增强VU研究和教育的基础设施，促进PI的科学领导和职业目标，目前，PI是VU物理学中唯一的女性教师。该研究有望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，并有助于研究和教育的整合。该项目由材料研究部和MPS OMA（多学科活动办公室）共同支持。