Molecular Assemblies in Multicomponent Linear Chain Solids

多组分线性链固体中的分子组装

• 批准号: 0071381
• 负责人: Douglas Dorset
• 金额: $ 27万
• 依托单位: Hauptman-Woodward Medical Research Institute Inc
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-06-15 至 2001-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0071381&HistoricalAwards=false
• 关键词: Molecular; Assemblies; Multicomponent; Linear; Chain

To characterize the solid state molecular interactions within binary and multicomponent polymethylene chain arrays, electron diffraction data from oriented single microcrystals will be employed to elucidate their crystal structures. This will provide a unique opportunity to uncover information (e.g. packing symmetry, unit cell dimensions, co-existence of similar crystalline polymorphs or alternate crystal structures, accommodation of non-overlap molecular volumes) previously hidden to powder diffraction investigations due to reflection overlap. Techniques developed in this laboratory will provide reliable intensity data from the most informative projections of the unit cell, in order to carry out quantitative direct structure analyses. Low dose electron microscopic lattice imaging will also depict interfaces at phase boundaries. Factors influencing the stabilization of solid solutions (chain length differences and length distribution, heterogroup and branch inclusions) will be studied, both for stable lamellae as well as incompletely separated lamellae that include long 'bridging molecules'. The progress of phase separation for two- and three-component metastable solid solutions within a miscibility gap will be characterized by electron crystallography to define the crystal packing of the final solids, in order to discern common features that would suggest a diffusion path. Crystallographic characterizations of eutectic solids will identify interfacial interactions across phase boundaries, testing the general occurrence of epitaxial interactions between these contacting domains.%%%The molecular and structural characterization of these polymeric materials is important in understanding and optimizing their properties. ***

为了表征二元和多组分聚亚甲基链阵列内的固态分子相互作用，来自定向单微晶的电子衍射数据将用于阐明它们的晶体结构。 这将为揭示以前由于反射重叠而隐藏在粉末衍射研究中的信息（例如堆积对称性、晶胞尺寸、相似晶体多晶型物或替代晶体结构的共存、非重叠分子体积的容纳）提供独特的机会。 该实验室开发的技术将从晶胞最丰富的投影中提供可靠的强度数据，以便进行定量直接结构分析。 低剂量电子显微晶格成像还将描绘相边界处的界面。 将研究影响固溶体稳定性的因素（链长差异和长度分布、杂基团和分支夹杂物），包括稳定的片层以及包含长“桥接分子”的不完全分离的片层。 混溶间隙内的两组分和三组分亚稳态固溶体的相分离过程将通过电子晶体学来表征，以定义最终固体的晶体堆积，以便辨别暗示扩散路径的共同特征。 共晶固体的晶体学表征将识别跨相边界的界面相互作用，测试这些接触域之间外延相互作用的一般发生情况。%%%这些聚合物材料的分子和结构表征对于理解和优化其性能非常重要。 ***