NIRT: One-,Two- and Three-Dimensional Superstructured Materials from Well-Defined, Complex Nanoscale Components

这个纳米尺度跨学科研究团队(NIRT)项目由国家科学基金会材料研究、化学和运输系统部门共同资助，将为生产和研究由稳定的纳米颗粒组件组成的一维、二维和三维超结构开发合成策略和表征方案。该合成方法包括在溶液中和在基质上系统地排列作为坚固的核-壳构建块的共聚物的交联组装体，以制造一维中观尺度(~100 nm至~1 mm)、二维微尺度(~1 mm至~100 mm)和三维宏观尺度(100 Mm)的对象，每个对象都由纳米构建块组成。其结果将是创建完全独特的复合形态，这些形态不能直接在共聚物的相图中获得。这一策略模仿了目前生命系统独有的纳米尺度的化学控制。利用纳米级有机超结构作为支架材料实现无机材料和生物大分子的纳米晶生长将是本研究的主要目标。有机超结构促进结晶和共结晶的机理将被详细研究。要测试的假设包括：(1)有机纳米颗粒将组装成定义良好的一维、二维和三维超结构，适合制造成有用的器件应用；(2)这种超结构将提供界面接触，模板结晶事件，以产生独特的和可控制的纳米晶相，从表面引发或通过共结晶；(3)有机超结构和纳米晶材料的性质将导致独特的物理、光学、磁性和力学性能。拟议活动的教育和研究方面将跨越几个学科(有机化学、生物学、物理化学、聚合物物理、化学和机械工程、材料科学)，以有效地研究由两个或更多纳米尺度的结构组成的一维、二维和三维超结构，以及模板化的无机/有机纳米晶材料。拟议中的研究充满了影响教育的机会。学生将从跨学科、多地点的研究活动中受益。在华盛顿大学为K-8级教师开发的外展课程(2001年秋季)将得到加强，并在参与机构实施。NIRT的重点还为社会教育纳米科学和纳米技术的好处创造了一个有效的平台。例如，所提出的纳米结构固体可能代表着用于医学的新的先进材料，如用于药物控制释放的“智能”水凝胶状涂层，以及用于组织工程的支架。这些材料也可能是下一代先进的分离介质、坚韧的光学透明固体、催化剂或用于制造纳米或微机械设备的纳米复合材料。热响应存储器件和悬臂梁传感器器件的复杂纳米涂层是一维、二维和三维超结构将被研究的特殊应用。此外，建议的材料将被评估为纳米表面，无机盐或生物大分子可以从纳米表面开始结晶。超结构的受控共结晶将作为骨生长中发现的纳米晶相的模型系统进行研究。

This Nanoscale Interdisciplinary Research Team (NIRT) project, co-funded by the National Science Foundation Divisions of Materials Research, Chemistry, and Chemical and Transport Systems, will develop synthetic strategies and characterization protocols for the production and study of one-, two- and three-dimensional superstructures composed of stabilized nanoparticle assemblies. The synthetic approach involves the systematic ordering, in solution and on substrates, of crosslinked assemblies of copolymers, as robust core-shell building blocks, to manufacture 1-dimensional meso-scale (~100 nm to ~1 mm), 2-dimensional micro-scale (~1 mm to ~100 mm) and 3-dimensional macro-scale (100 mm) objects, each comprised of nanoscopic building blocks. The result will be the creation of entirely unique composite morphologies that are not accessible in the phase diagrams of the copolymers directly. This strategy mimics the control of chemistry at the nanometer scale that is currently the exclusive province of living systems. Utilization of the nanoscale organic-based superstructures as scaffolds for the initiation of nanocrystalline growth of inorganic materials and biomacromolecules will be a key goal of the investigation. The mechanisms by which the organic superstructures promote crystallization and co-crystallization will be studied in detail. The hypotheses to be tested include: (1) organic nanoparticles will be assembled into well defined one-, two- and three-dimensional superstructures, suitable for fabrication into useful device applications; (2) such superstructures will present interfacial contacts that template the crystallization events to produce unique and controllable nanocrystalline phases, initiated from a surface or via co-crystallization; (3) the nature of the organic superstructures and the nanocrystalline materials will result in unique physical, optical, magnetic, and mechanical properties.The educational and research aspects of the proposed activities will cross several disciplines (organic chemistry, biology, physical chemistry, polymer physics, chemical and mechanical engineering, and materials science) to address effectively the study of one-, two-, and three-dimensional superstructures, composed of two or more nanoscale constructs, and of templated inorganic/organic nanocrystalline materials. The proposed research is rich with opportunities to impact education. Students will benefit through interdisciplinary, multi-site research activities. An outreach course developed (Fall 2001) at Washington University for K-8 teachers will be enhanced and implemented at the participating institutions. The focus of this NIRT also creates an effective platform for societal education of the benefits of nanoscience and nanotechnology. For example, the proposed nanostructured solids may represent new advanced materials for medicine, such as "smart" hydrogel-like coatings for controlled release of drugs, and scaffolds for tissue engineering. These materials may also be the next generation of advanced separation media, tough optically clear solids, catalysts or nanocomposites used in the fabrication of nano- or micro-mechanical devices. Thermally-responsive memory devices and complex nanoscopic coatings for cantilever-based sensor devices are particular applications that will be investigated for the 1-, 2-, and 3-dimensional superstructures. Additionally, the proposed materials will be evaluated as nanoscopic surfaces from which the crystallization of inorganic salts or biomacromolecules can initiate. The controlled co-crystallization of the superstructures will be investigated, as a model system for the nanocrystalline phases found in bone growth.