Preparation of Ultrafine Magnetic Particles Using Microemul-sions and Vesicles

微乳液和囊泡制备超细磁性颗粒

• 批准号: 8922574
• 负责人: Dinesh Shah
• 金额: $ 22.08万
• 依托单位: University of Florida
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1990
• 资助国家: 美国
• 起止时间: 1990-09-01 至 1992-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8922574&HistoricalAwards=false
• 关键词: Preparation; Ultrafine; Magnetic; Particles; Using

In recent years, there has been an increasing demand for the preparation of ultrafine magnetic oxides of uniforms size which are mainly used in computer data storage, audio and video recording, magnetic fluids and fabrication of certain microwave devices. The difficulty of obtaining uniform-sized nanoparticles of magnetic oxides stems from the fact that their preparations are mostly done in bulk aqueous media in which uncontrolled nucleation and grain growth cannot be prevented. Synthesis of these compounds (gamma-Fe2O3, Fe3O4, CrO2, Cobalt doped Fe2O3 and barium ferrite) in constrained microreactors such as the aqueous cores of water-in-oil microemulsions or the inner part of single-compartment vesicles seems to be a promising alternative although these techniques are still under development. In this project, methods are used to optimize and control the ultralow size and the narrow particle size distribution by proper modulation of certain physico-chemical conditions of the microemulsion and vesicular systems. Further, the project examines how to make quantitative correlations between the morphology (size, shape, and size-distribution) and structure of the product microparticles and the physico-chemical properties of the surfactant system. The results of the study delineate the similarities as well as the differences between the two types of microreactors (microemulsions and vesicles) in relation to chemical reactions in them. The solid precipitate obtained from such microreactors may be different from that precipitated in a large aqueous medium. Not only might these experiments lead to the production of monodispersed ultrafine magnetic particles, but they might also provide a greater fundamental understanding of interfacial chemistry in relation to nucleation and crystal growth in microreactors. This project exploits the expertise of two research groups (Rhode Island and University of Florida).

近年来，对 均匀尺寸的超细磁性氧化物的制备方法 主要用于计算机数据存储、音频和 视频记录、磁流体和制造某些 微波设备 获得统一尺寸的难度 磁性氧化物的纳米颗粒源于这样一个事实， 它们的制备主要在本体水性介质中进行， 不受控制的成核和晶粒生长不能 防止。 这些化合物（γ-Fe 2 O3，Fe 3 O 4， CrO 2、掺杂钴的Fe 2 O3和钡铁氧体） 微反应器例如油包水的含水核 微乳液或单室内部 囊泡似乎是一个有前途的选择，虽然这些 技术仍在开发中。 在本项目中，使用方法来优化和控制 超小尺寸和窄粒度分布， 适当调节某些物理化学条件， 微乳液和囊泡体系。 此外，该项目 研究如何使定量之间的相关性， 形态（大小、形状和大小分布）和结构 产品微粒和物理化学 表面活性剂体系的性质。 研究结果 描述了它们之间的相似之处和不同之处 两种类型的微反应器（微乳液和囊泡） 与其中的化学反应有关。 固体 从这样的微反应器获得的沉淀物可以不同 从在大的水性介质中沉淀的。 不仅 这些实验是否会导致 单分散的超细磁性颗粒，但它们可能 也提供了一个更大的基本理解， 成核与结晶界面化学 微反应器中的生长 这个项目利用了 两 研究小组（罗得岛和佛罗里达大学）。