Effect of Chain Length on Polymer Stereocomplexation: A Quantitative Study
Effect of Chain Length on Polymer Stereocomplexation: A Quantitative Study
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链长对聚合物立体络合的影响：定量研究
DOI：
10.1021/acs.macromol.1c00380
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发表时间：
2021
期刊：
影响因子：
5.5
通讯作者：
Dong Xue-Hui
中科院分区：
文献类型：
--
作者：
Zhou Dongdong;Xu Miao;Li Jinbin;Tan Rui;Ma Zhuang;Dong Xue-Hui
立体络合主要依赖于组成对映体链的链长和化学计量比。然而，长期以来，对其独立贡献的定量理解一直受到固有分子量分布的影响。在这项工作中，我们制备了一个离散的低聚-丙交酯和低聚D-丙交酯的文库，并系统地研究了它们的立体配位行为。通过预先设计的配方，可以精确地调节两种互补低聚物的相对链长和摩尔比。当两个对映体具有完全相同的链长(x1=x2，其中是重复单元的数目)时，它们共结晶成具有延伸链构象的高度均匀的立体配合物。另一方面，当两个组分的大小不相等时，根据链长差异和化学计量比，较长组分的多余链段可能在片状晶体的基面上保持无定形(ifx1<；x2≤2x1)或与其他短对映体(ifx2>；2x1)络合。这项研究可以加深我们对立体络合的基本认识，为合理的结构工程提供良好的机会。
Stereocomplexation critically depends on the chain length and stoichiometry of constituent enantiomeric chains. Quantitative understanding of their independent contribution, however, has long been compromised by inherent molecular weight distribution. In this work, we prepared a library of discreteoligol-lactide andoligoD-lactide and systematically explored the stereocomplexation behaviors. The relative chain length and mole ratio of the two complementary oligomers can be precisely regulated with predesigned recipes. When the two enantiomers have exactly the same chain length (x1=x2, wherexis the number of repeat units), they co-crystallize into highly uniform stereocomplexes with extended chain conformation. On the other hand, when the two components are not of equivalent size, the excess segments of the longer ones could stay amorphous on the basal surfaces of the lamellar crystal (ifx1<x2≤ 2x1) or complex with other short enantiomers (ifx2> 2x1), depending on the chain length difference and stoichiometry. This study could enhance our fundamental understanding of stereocomplexation, providing promising opportunities for rational structure engineering.