CAREER: Magnetic-Nanocrystal Self-Assembled Superlattices

9733160王：本基金研究磁性纳米晶超晶格材料的合成和表征。为了利用纳米团簇的尺寸特异性和选择性所提供的技术优势，必须了解制备宏观数量和高标准的尺寸、结构形态和形状均匀度的团簇组装材料的基本方法。这些都是系统探索由这种建筑单元组装的图案化上部结构的性质，以及制定设计和控制这种新型组装材料的方法的关键步骤。主要的研究目标是：合成、表征和测定Co、y-Fe2O_3和Fe_3O_4自组装钝化磁性纳米晶超晶格的性质；测定纳米颗粒和超晶格的体相和表面微结构，以了解纳米晶之间的磁耦合/去耦合；考察纳米颗粒、表面活性剂和超晶格的原位结构演变和相变，以预测用于器件应用的体系的稳定性、可靠性和耐久性，并对纳米晶体及其组装的结构和行为进行模拟。教育努力集中在以下领域：合作的研究生论文项目的发展，扩大外展计划，为高中生和公众开发交互式显微显示器，以及与材料科学相关的跨学科教学实验的发展。%的纳米粒子，以及它们所具有的物理和化学功能的特异性和选择性，表明它们是二维和三维团簇自组装超晶格结构的理想构建块。自组装阵列可以包括自组织成单分子层、薄膜和包裹在保护性致密有机涂层中的尺寸选择的纳米团簇的超晶格。图案化磁性纳米晶体由于其在信息存储、彩色成像、生物处理、磁制冷和磁流体等方面的潜在应用，在科学和技术上都具有重要的意义。***

9733160 Wang This grant explores synthesis and characterization of magnetic nanocrystal superlattice materials. To utilize the technological advantages offered by the size specificity and selectivity of nanoclusters, it is imperative to understand the fundamental methodologies for preparation of cluster assembled materials in macroscopic quantities and with high standards of size, structural morphological and shape uniformity. These are vitally important steps toward a systematic exploration of the nature of patterned superstructures assembled from such building units, as well as the formulation of methods for designing and controlling such novel assembled materials. The major research objectives are: to synthesize, characterize, and determine the properties of self-assembly passivated magnetic nanocrystal superlattices of Co, y-Fe2O3 and Fe3O4; to determine the bulk and surface microstructures of the nanoparticles and the superlattices for understanding the magnetic coupling/decoupling among nanocrystals as a function of the interparticle distance; to examine the in- situ structure evolution and phase transformation of the nanoparticles, the surfactant and the superlattices for predicting the stability, reliability and durability of the system for device applications, and to model the structure and behavior of nanocrystals and their assemblies. Education efforts are concentrated in the areas of development of collaborative graduate student thesis projects, expansion of outreach programs, development of interactive microscopy displays for high school students and the public, and development of interdisciplinary teaching experiments related to materials science. %%% Nanocusters, and the physical and chemical functional specificity and selectivity they possess, suggest that they are ideal building blocks for two-and three-dimensional cluster self-assembled superlattice structures. Self- assembled arrays can involve self-organization into monolayers, thi n films, and superlattices of size-selected nanoclusters with encapsulated in protective compact organic coatings. Patterned magnetic nanocrystals are of vital interest both scientifically and technologically because of their potential applications in information storage, color imaging, bioprocessing, magnetic refrigeration, and ferrofluids. ***