CAREER: Synthesis of Polymer Coated Magnetic Colloids and Assembly into Mesoscopic Nanoparticle Chains

技术摘要：拟议的研究将集中在开发一类新型的有机/无机混合纳米粒子作为分层自组装材料的构建块。 聚合物包覆的磁性纳米粒子的合成、表征和组装的基本方面将是本提案的重点。 拟议的研究的智力价值是能够制备复杂的复合材料，具有分子，纳米和介观尺度制度的控制结构。一个多功能的合成方法的发展，准备一个库的功能铁磁胶体将最初追求。 这种方法的核心是使用定义明确的聚合物来制备和功能化能够进行1-D磁性组装的铁磁纳米颗粒。可控自由基聚合将是高分子表面活性剂设计和合成的核心。第二个关键的努力，将被调查的功能铁磁纳米粒子的表面上，在溶液中和聚合物薄膜的控制组装。 颗粒尺寸，磁化强度和施加的磁场的影响将被调查，以确定最佳的条件，1-D组装和排列在各种矩阵。 预计这些领域的发展将使功能性磁性纳米颗粒的组装和共价连接成为永久连接的链。 这些功能1-D组件预计是介观类似物的聚合物链。 使用各种成像技术（例如，利用原子力显微镜（AFM）、透射电镜（TEM）、热分析和力学性能评价等手段，研究了不同形貌组装材料的结构与性能之间的关系。 非技术概述：将合成有机聚合物和金属颗粒并将其组合以制备具有可调组成的有机壳和无机磁性核的核-壳复合材料。 这些材料将在纳米尺度上杂化，作为制备具有协同性能的新型材料的一种方法。 这些材料的磁性将被用来将这些混合纳米粒子自组装成长度为微米的纤维状结构。 这项工作预计将影响微电子和光电器件的许多领域，因为它能够在很宽的长度尺度范围内控制结构。 拟议的研究是高度跨学科的，并为高中，本科和研究生水平的学生提供机会，以了解聚合物和纳米材料的重要性。 拟议的研究与教育推广的整合将通过指导高中学生和教师在亚利桑那大学进行的研究经验，由首席研究员实现。 由这个学生教师团队实施的研究将通过与校园内的本科研究项目的综合互动来传播。 重点将放在图森代表性不足的少数民族学生的辅导和发展上。

TECHNICAL SUMMARY:The proposed research will focus on the development of a novel class of organic/inorganic hybrid nanoparticles as building blocks for hierarchically self-assembled materials. The fundamental aspects of the synthesis, characterization and assembly of polymer coated magnetic nanoparticles will be the focus of this proposal. The intellectual merit of the proposed research is the ability to prepare complex composite materials possessing controlled structure on molecular, nano- and mesoscale regimes. The development of a versatile synthetic methodology to prepare a library of functional ferromagnetic colloids will be initially pursued. Central to this approach is the use of well-defined polymers to prepare and functionalize ferromagnetic nanoparticles that are capable of 1-D magnetic assembly. Controlled radical polymerization will be central in the design and synthesis of polymeric surfactants. A second critical effort that will be investigated is the controlled assembly of functional ferromagnetic nanoparticle on surfaces, in solution and in polymer thin films. The effect of particle size, magnetization and applied magnetic fields will be investigated to determined optimal conditions for 1-D assembly and alignment in various matrices. Development of these areas is anticipated to enable the assembly and covalent linkage of functional magnetic nanoparticles into permanently linked chains. These functional 1-D assemblies are expected to be mesoscale analogues to polymer chains. Characterization of these materials using various imaging techniques (e.g., AFM, TEM), thermal analysis and mechanical property evaluation will be conducted to ascertain structure-property correlations of assembled materials possessing different morphologies. NON-TECHNICAL SUMMARY:Organic polymers and metallic particles will be synthesized and combined to prepare core-shell composite materials possessing an organic shell with tunable composition and an inorganic magnetic core. These materials will be hybridized on the nanoscale as an approach to prepare novel materials with synergistic properties. The magnetic properties of the materials will be utilized to self-assemble these hybrid nanoparticles into fiber-like structures spanning microns on length. This work is anticipated to impact a number of areas in microelectronics and optoelectronic devices due to the ability to control structure over a broad range of length scales. The proposed research is highly interdisciplinary and offers opportunities for students at high school, undergraduate and graduate levels to appreciate the importance of polymers and nanomaterials. Integration of the proposed research with educational outreach will be achieved by the mentoring of high school students and teachers in research experiences carried out at the University of Arizona by the principal investigator. Research implemented by this student-teacher team will be disseminated by integrated interactions with undergraduate research programs on campus. Emphasis will be placed on the mentoring and development of students from under-represented minorities in Tucson.