Self-Assembly of Macromolecules Within Single Topological Defects of Nematic Solvents
Self-Assembly of Macromolecules Within Single Topological Defects of Nematic Solvents
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DOI：
10.1021/acs.chemmater.0c02415
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发表时间：
2020-08-11
影响因子：
8.6
通讯作者：
Abbott, Nicholas L.
中科院分区：
文献类型：
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作者：
Noh, JungHyun;Cao, Wei;Abbott, Nicholas L.
溶剂介导的大分子自组装已被广泛用作合成纳米结构材料的自下而上策略，但大多数溶剂（例如，水或各向同性的有机溶剂）对单个组件的空间定位和操作提供有限的控制。在这项研究中，我们使用的有机溶剂的有序性，探索编程组装的聚合物与定制的侧链内的拓扑缺陷的纳米级核心的有序溶剂的结构-性能关系的可能性。聚（丙烯酸正烷基酯）（烷基=丁基，己基，和十二烷基）的侧链的变化表明，驱动力的分区的聚合物到纳米级的核心的拓扑缺陷形成在正戊基-4-联苯腈（5CB）的侧链长度增加，但没有观察到受控的自组装。聚（二甲基丙烯酰胺）被认为是可溶于散装的PANSCB，但没有分区的缺陷和聚（2-羟乙基丙烯酸酯）聚集在PANSCB溶剂之前，分区的缺陷。然而，聚（2-羟乙基甲基丙烯酸酯）优先分配到缺陷的临界浓度以上，形成单一的，明确的，和可逆的组件（在体相聚集的情况下）在由缺陷的位置所定义的位置。通过合成含有蒽侧链的共聚物，可以在缺陷中产生横截面直径为30 +/- 5 nm的光交联组装体并从缺陷中恢复。总体而言，本研究提供了设计参数的液晶溶剂的拓扑缺陷，包括聚合物侧链结构（极性，灵活性和氢键性质），聚合物分子量，和主链的性质的程序化聚合物组装。
Solvent-mediated self-assembly of macromolecules has been widely used as a bottom-up strategy for the synthesis of nanostructured materials, but most solvents (e.g., water or isotropic organic solvents) provide limited control over the spatial localization and manipulation of individual assemblies. In this study, we use organic solvents with nematic ordering to explore the possibility of programmed assembly of polymers with tailored side chains within the nanoscopic cores of topological defects of the nematic solvents by developing structure-property relationships. Variation of the side chains of poly(n-alkyl acrylates) (alkyl = butyl, hexyl, and dodecyl) revealed that the driving force for the partitioning of the polymers into the nanoscopic cores of topological defects formed in nematic 4'-n-pentyl-4-biphenylcarbonitrile (5CB) increased with side-chain length, but controlled self-assembly was not observed. Poly(dimethylacrylamide) was found to be soluble in bulk nematic SCB but did not partition to defects and poly(2-hydroxyethyl acrylate) aggregated in the nematic solvents prior to partitioning to defects. However, poly(2-hydroxyethyl methacrylate) preferentially partitioned into defects above a critical concentration, forming single, well-defined, and reversible assemblies (in the absence of aggregation in the bulk phase) at locations defined by the positions of the defects. By synthesizing copolymers that incorporated anthracene side chains, photo-cross-linked assemblies with cross-section diameters of 30 +/- 5 nm could be generated in and recovered from the defects. Overall, this study provides design parameters for programmed polymer assembly in topological defects of liquid crystalline solvents, including the polymer side-chain structure (polarity, flexibility, and hydrogen bonding properties), polymer molecular weight, and properties of the main chain.