Cylindrical and Spherical Supermolecules from Polymer Backbones Jacketed with Dendritic Coats

本研究将设计具有良好定义的扁平锥形和圆锥形的单晶建筑模块库，这些模块可自行组装成圆柱形和球形。这些超分子将生成柱状六角形和球形热致和溶致液晶（LC）相。这些LC相将保证其组装的热力学控制，并允许通过x射线衍射确定其形状。用可聚合基团功能化的扁平锥形和圆锥形单枝构建块库将通过活体方法聚合，以产生直径和长度分别控制在纳米级的圆柱形和球形巨型聚合物的第一个例子。这些巨大的枝状单体在LC组装中的组织也将用于聚合过程中在人工提高浓度和限制几何形状的反应器中聚集它们的可聚合基团，因此，将产生一种控制聚合的新方法。这项研究将为聚合物材料的设计提供一个入口，这些材料具有可预测的和由其形状决定的显著不同的性能。在树突涂层的柔性骨架上获得的圆柱形和球形巨型聚合物将获得新的机制来控制其柔性链的构象和刚度，而不考虑其战术性。以可逆和可控的方式改变聚合物形状从棒状到球形的机制将被详细阐述。预计这些圆柱形3-D聚合物将产生比目前已知的1-D线性刚性棒更刚性的结构。这项研究将把自然界的概念移植到复杂的合成高分子材料领域。自然系统为能量和信息的储存和转移以及结构材料的生产提供了最有效的机制。该计划开发的聚合物系统将提供新的技术概念，这将允许首次开发新材料，如功能纤维，薄膜，膜，粘度控制器，电子，光子和控制释放系统，通过自然在漫长的进化过程中阐述的原理，具有外部调节的物理特性。＊＊＊

9708581 Percec This research will design libraries of monodendritic building blocks with well defined flat tapered and conical shapes which self-assemble into cylindrical and respectively spherical shapes. These supermolecules will generate columnar hexagonal and spherical thermotropic and lyotropic liquid crystalline (LC) phases. These LC phases will warrant a thermodynamic control of their assembly and will allow the determination of their shape by X-ray diffraction. Libraries of flat tapered and conical monodendritic building blocks functionalized with polymerizable groups will be polymerized via living methods to generate the first examples of giant polymers with cylindrical and spherical shapes with diameter and length and respectively diameter controlled at the nanoscale level. The organization of these giant dendritic monomers in a LC assembly will also be used to aggregate their polymerizable groups in a reactor of artificially enhanced concentration and restricted geometry during the polymerization process and therefore, will generate a new approach to the control of polymerization. This research will provide an entry into the design of polymeric materials with predictable and dramatically different properties which are determined by their shape. Cylindrical and spherical giant polymers obtained from flexible backbones jacketed with dendritic coats will access new mechanisms to control the conformation and rigidity of their flexible chain regardless of their tacticity. Mechanisms to change in a reversible and controlled way the shape of the polymer from rod-like to spherical will be elaborated. It is expected that these cylindrical 3-D polymers will produce more rigid structures than the currently known 1-D linear rigid-rods. %%% This research will transplant concepts from Nature into the field of complex synthetic polymeric materials. Natural systems provide the most efficient mechanisms for the storage and transfer of energy and information and for the production of structural materials. The polymeric systems developed by this program will provide new technologic concepts which will allow for the first time the development of new materials such as functional fibers, films, membranes, viscosity controllers, electronic, photonic and controlled release systems with externally regulated physical properties via principles elaborated by Nature during the long process of evolution. ***