Synergistic Physiochemical Properties of Macromolecule-Metal Complexes

这一研究活动的重点是开发具有协同热物理性质的大分子-金属络合物，以及对潜在络合物的光谱检测。元素周期表中d-块和f-块的金属阳离子就像磁铁一样，诱导功能聚合物占据金属中心第一壳层配位的空位。因此，在固体聚合物复合体中形成自组装的限制迁移率的纳米团簇，使人们能够设计出能够在失效发生之前承受更大的力，在粘性流动或热降解之前承受更高温度的材料。这是超分子设计的延伸，代表了跨学科高分子科学和工程的一个新前沿。有机-无机杂化材料有望对纳米技术的最新发展做出重大贡献，并通过分子工程制造出具有异常新的和有用的性能的器件。在分子水平上，将使用高分辨率碳-13固体核磁共振和傅立叶变换红外光谱来探测影响金属配位驱动微混合的微环境因素。当顺磁性过渡金属盐与感兴趣的聚合物形成络合物时，将进行磁化率测量，以研究这些纳米团簇的自旋玻璃性质，这些自旋玻璃性质负责独特的宏观物理性质。玻璃化转变附近的磁化率与温度的关系是前所未有的。这位首席研究员对大分子-金属络合物的知识现状做出了重大贡献，但科学文献数据库表明，在光谱水平上没有太多的活动来支持所提出的金属-配体相互作用模型，特别是当这些络合物的解离与玻璃化转变过程相一致时。在分子水平上，金属配位驱动的相互作用可以在一些实用的科学和技术领域得到开发。例如，可以(I)增容在没有无机成分的情况下不相容的聚合物，(Ii)通过沉淀过渡金属PI-络合物来分离烯烃和烷烃的混合物(即，烯烃/石蜡混合物)，(Iii)通过桥链和增加其分子量来改变聚合物溶液的粘度(即，粘稠化)，(Iv)通过包含捕获的金属阳离子的凝胶材料在交流电场的存在下的循环膨胀和收缩来诱导凝胶和模拟人工肌肉对神经脉冲的反应，以及(V)通过含有对这些有毒化合物起磁铁作用的官能团的水溶性聚合物，从废水中去除重金属污染物。本研究项目中正在研究的基础研究将直接影响到这五个具有实际意义的领域中高分子-金属络合物的设计和使用。

This research activity focuses on the development of macromolecule-metal complexes that exhibit synergistic thermophysical properties, and the spectroscopic detection of the underlying complexation. Metal cations from the d-block and the f-block in the Periodic Table act like magnets that induce functional polymers to occupy vacant sites in the first-shell coordination sphere of the metal center. Consequently, the formation of self-assembled mobility-restricting nanoclusters in solid polymeric complexes allows one to design materials that can withstand larger forces before failure occurs and higher temperatures prior to viscous flow or thermal degradation. This is an extension of supramolecular design that represents a new frontier in interdisciplinary macromolecular science and engineering. Organic-inorganic hybrid materials are expected to contribute significantly to the state-of-the-art in nanotechnology, and yield devices with unusually new and useful properties via molecular engineering. At the molecular level, high-resolution carbon-13 solid state NMR and Fourier transform infrared spectroscopies will be used to probe microenvironmental factors that influence metal-based coordination-driven micromixing. When paramagnetic transition metal salts form complexes with the polymers of interest, magnetic susceptibility measurements will be performed to investigate the spin-glass nature of these nanoclusters that are responsible for unique macroscopic physical properties. Temperature dependence of magnetic susceptibilities in the vicinity of the glass transition is unprecedented. The principal investigator has contributed significantly to the current state of knowledge of macromolecule-metal complexes, yet scientific literature databases suggest that there has not been much activity at the spectroscopic level to support the proposed models for metal-ligand interaction, particularly when the dissociation of these complexes coincides with the glass transition process.Metal-based coordination-driven interactions at the molecular level can be exploited in several practical areas of science and technology. For example, it is possible to (i) compatibilize polymers that are immiscible in the absence of the inorganic component, (ii) separate mixtures of alkenes and alkanes (i.e., olefin/paraffin blends) via precipitation of transition metal pi-complexes, (iii) modify the viscosity (i.e., viscosification) of polymer solutions by bridging chains and increasing their molecular weight, (iv) induce gelation and simulate the response of artificial muscles to neural impulses via cyclic expansion and contraction of gelatinous materials that contain trapped metal cations in the presence of AC electric fields, and (v) remove heavy metal contaminants from wastewater streams via water-soluble polymers that contain functional groups which act as magnets for these toxic compounds. The fundamental studies under investigation in this research project will have a direct influence on the design and use of macromolecule-metal complexes in these five areas of practical interest.