Fractal Nanoarchitectures

技术综述：通过定向和自组装技术构建的高分子材料的性能将被研究。精确制造非树枝状、金属基(带电)的分形聚合物的能力(通过三联吡啶-金属-三联吡啶连接性)将为创造许多基于离子相互作用的新材料奠定基础(与树枝状大分子、经典聚合物和其他基于分形的结构)。已经证明，这些分形自组装成有序的纤维和棒；引入适当带电的物种作为反离子，(如树枝状大分子、卟啉和氧化的碳纳米管)有望(1)导致具有新的和有趣的电子现象的新材料，(2)提供能量存储和释放装置。在聚合物分形块中加入刚性形状持久性将稳定形成能够作为(1)催化、(2)分子包裹体或(3)单壁碳纳米管连接器的“大分子大小”空心区的三维框架。在联吡啶CuII与羧酸盐离子配位方面的工作已经导致了可逆的碳纳米管网络的形成。将这种配位现象与端羧酸盐端基的树枝状大分子相结合，将允许创建基于围绕铜结合的树枝状大分子形成聚合网络的能力(随后定量去除铜配位物种)的“球内球”的无限制旋转。使用具有被遮盖的羧酸末端的联吡啶部分将有助于在球内形成多个球体，可以被比作“巴基洋葱”。将制作多层不同金属的薄膜，并研究它们的可调谐电子特性。非技术摘要：新材料将基于带电物种的物理相互作用及其以精确有序的方式匹配或封装的潜力来构建。这将导致新型电子设备的出现，如分子电池。具有自由旋转内部球形元件的新型球形材料将被研究用于有毒物质的屏蔽和分子尺度的指南针。这些研究领域对于微电子机械系统、传感器和新的光伏设备部件的“小型化”具有重要意义。教育机会来自各级科学家的培训和发展。通过首席调查员网站(www.endrimers.com)以及在地区学校、大学和会议上的专题介绍来宣传教育宣传，该网站目前每月平均有6 000至7 000次访问。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.