Fractal Nanoarchitectures

技术概要：将研究通过定向和自组装技术构建的高分子材料的性质。精确制造非树枝状、金属基（带电）分形聚合物（通过三联吡啶-金属-三联吡啶连接）的能力将为创造许多基于离子相互作用的新材料（与树枝状聚合物、经典聚合物和其他基于分形的结构）奠定基础。已经证明，这些分形自组装得到有序的纤维和棒;引入适当带电的物种作为抗衡离子（如树枝状聚合物，卟啉和氧化的碳纳米管）预计将（1）导致具有新的和有趣的电子现象的新材料和（2）提供能量存储和释放设备。在聚合物分形的构建块内引入刚性形状持久性将稳定三维框架，以形成能够充当（1）催化、（2）分子包含或（3）单壁碳纳米管的连接器的位点的“大分子尺寸”空隙区域。在三联吡啶CuII与羧酸根离子的配位领域的工作已经导致了可逆碳纳米管网络的制作。将这种配位现象与羧酸盐封端的树枝状聚合物相结合，将允许产生具有不受限制的旋转的“球内球”，其基于在铜结合的树枝状聚合物周围形成聚合网络的能力（随后定量去除Cu配位物质）。采用具有掩蔽的羧酸酯末端的三联吡啶部分将促进多个球内球的产生，其可以被比作“巴基洋葱”。“将制作具有不同金属的多层膜，并研究其可调电子特性。非技术性总结：新材料将基于带电物质的物理相互作用及其以精确有序的方式组装的潜力来构建。这将导致新类型的电子设备，如分子电池。将研究具有自由旋转内部球形元件的新型球形材料，以用作有毒材料的防护罩和分子级指南针。这些研究领域对于微机电系统、传感器和新型光伏器件的“小型化”非常重要。教育机会来自各级科学家的培训和发展。通过主要调查员的网站（www.dendrimers.com）宣传教育推广活动，目前平均每月访问6 000至7 000次，并在地区学校、大学和会议上作介绍。工业和国际合作将继续支持跨学科整合的必要性。

TECHNICAL SUMMARY: The properties of macromolecular materials constructed by directed- and self-assembly techniques will be studied. The ability to precisely craft non-dendritic, metal-based (charged) fractal polymers (via terpyridine-metal-terpyridine connectivity) will lay the foundation to create many new materials based on ionic interactions (with species such as dendrimers, classical polymers, and other fractal-based constructs). It has been demonstrated that these fractals self-assemble to give ordered fibers and rods; the introduction of appropriately charged species as counter ions, (such as dendrimers, porphyrins, and oxidized carbon nanotubes) is expected to (1) lead to novel materials possessing new and interesting electronic phenomena and (2) provide energy storage and release devices. Incorporation of rigid shape-persistence within the building blocks of the polymeric fractals will stabilize a 3-dimensional framework for forming "macromolecular-sized" void regions capable of acting as sites for (1) catalysis, (2) molecular inclusion or (3) connectors for single-walled carbon nanotubes. Work in the area of terpyridineCuII coordination with carboxylate ions has already led to the crafting of reversible carbon nanotube networks. Combining this coordination phenomenon with carboxylate-terminated dendrimers will allow the creation of "spheres-within-spheres" with unrestricted rotation predicated on the ability to form a polymerized network around the copper-bound dendrimer (followed by quantitative removal of the Cu-coordinating species). Employing terpyridine moieties possessing masked, carboxylate termini will facilitate the creation of multiple spheres-within-spheres that can be likened to "bucky onions." Multiple layers with differing metals will be crafted and their tunable electronic characteristics will be investigated.NON-TECHNICAL SUMMARY:New materials will be constructed based on the physical interactions of charged species and their potential to fit, or pack, in a precisely ordered manner. This will lead to new types of electronic devices, such as molecular batteries. New spherical materials possessing freely rotating internal spherical elements will be studied for use as shields for toxic materials and a molecular-scale compass. These areas of research are important with respect to the "miniaturization" of components for micro-electro-mechanical systems, sensors, and new photovoltaic devices. Educational opportunities arise from the training and development of scientists at all levels. Educational outreach is promulgated through the principal investigator's website (www.dendrimers.com), which currently averages 6,000-7,000 visits per month, as well as presentations at area schools, universities and conferences. Industrial and international collaborations will continue supporting the necessity of interdisciplinary integration.