Impact of pendant substituents on post-polymerization functionalization and electronic properties in stereoregular non-conjugated pendant electroactive polymers
Impact of pendant substituents on post-polymerization functionalization and electronic properties in stereoregular non-conjugated pendant electroactive polymers
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DOI：
10.1016/j.polymer.2023.126156
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发表时间：
2023-08
期刊：
影响因子：
4.6
通讯作者：
Alexander Schmitt;Negar Kazerouni;B. Thompson
中科院分区：
文献类型：
--
作者：
Alexander Schmitt;Negar Kazerouni;B. Thompson
最近关于非共轭侧基电活性聚合物（NCPEP）的报道已经证明了改变结构变量的重要性，特别是立构规整性、侧基的性质和将该基团连接到主链的间隔基的长度，以调节其光电性质。允许选择性地研究调节这些变量的影响而没有变化的分子量和构象的额外叠加影响的唯一合成方法是聚合后官能化方法，其中首先合成母体聚合物，然后用相应的侧基和间隔基官能化。然而，特别是对于侧基本身的调节，这种聚合后官能化方法的范围在很大程度上仍然未被探索。在这里，建立的光化学硫醇烯后聚合方法与各种侧基的兼容性进行了研究，通过使用有机锂引发剂的阴离子聚合的有规立构和立构无规聚（甲基丙烯酸烯丙酯）的官能化。咔唑和一个家庭的四个3，6-二取代咔唑与苯基，甲氧基，腈和叔丁基取代基作为各自的侧基进行了研究。用苯基、甲氧基和腈取代的侧基，可以证明由于有限的溶解度和对光化学副反应的脆弱性而限制硫醇-烯方法的范围。与此相反，叔丁基取代基不妨碍聚合后官能化。对相应的功能化NCPEPs进行了表征，并讨论了咔唑侧基被叔丁基取代对聚合物光电性能的影响。总体而言，这项工作证明了硫醇-烯官能化方法的关键限制以及它们在应用于不同取代的侧基时的起源。
Recent reports on non-conjugated pendant electroactive polymers (NCPEPs) have demonstrated the significance of altering structural variables specifically the stereoregularity, the nature of the pendant group and the length of the spacer connecting that group to the backbone for tuning of their optoelectronic properties. The only synthetic approach that allows for selectively studying the effects of tuning these variables without additional superimposed effects of varied molecular weights and tacticities is the post-polymerization functionalization methodology in which parent polymers are synthesized first and then functionalized with the respective pendant groups and spacers. However, specifically for tuning of the pendant group itself, the scope of such post-polymerization functionalization methods remains largely underexplored. Here, the compatibility of the established photochemical thiol-ene post-polymerization method with various pendant groups is investigated for functionalization of stereoregular and stereorandom poly(allyl methacrylates) made via anionic polymerization using an organolithium initiator. Carbazole and a family of four 3,6-disubstituted carbazoles with phenyl, methoxy, nitrile andt-butyl substituents were investigated as the respective pendant groups. With the phenyl, methoxy and nitrile substituted pendant groups limitations of the scope of the thiol-ene methodology due to limited solubility and vulnerability to photochemical side reactions could be demonstrated. In contrast,t-butyl substituents did not impede the post-polymerization functionalization. The corresponding functionalized NCPEPs were characterized and effects of substitution of the carbazole pendant group witht-butyl groups on the optoelectronic properties of the polymers are discussed. Overall, this work demonstrates critical limitations of the thiol-ene functionalization method as well as their origin when applied to differently substituted pendant groups.