Poly(3-(2,5-dioctylphenyl)thiophene) Synthesized by Direct Arylation Polycondensation: End Groups, Defects, and Crystallinity
Poly(3-(2,5-dioctylphenyl)thiophene) Synthesized by Direct Arylation Polycondensation: End Groups, Defects, and Crystallinity
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通过直接芳基化缩聚合成的聚(3-(2,5-二辛基苯基)噻吩)：端基、缺陷和结晶度
DOI：
10.1021/acs.macromol.6b01795
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发表时间：
2016
期刊：
影响因子：
5.5
通讯作者：
M. Sommer
中科院分区：
文献类型：
--
作者：
D. Schiefer;H. Komber;F. Mugwanga Keheze;S. Kunz;R. Hanselmann;G. Reiter;M. Sommer
π 共轭聚合物的一项核心特性是聚合物主链通过 π 轨道直接接触进行分子间相互作用的能力。聚(3-(2,5-二辛基苯基)噻吩) (PDOPT) 是一个显着的例外，因为庞大的侧链阻碍了主链 π-π 相互作用。然而，由于叉指正辛基侧链的侧链结晶，PDOPT 是半结晶的，因此任何与完美区域规整性的偏差都会严重影响结晶。在这里，我们首次通过直接芳基化缩聚（DAP）合成了PDOPT，并分析了各种反应条件对分子量、端基、缺陷结构、结晶度和形貌的影响。尽管通过 DAP 包括本体聚合对 PDOPT 合成进行了广泛优化，但由于链端脱卤，MW 仅限于 Mn,SEC∼ 10 kg/mol。进行了广泛的核磁共振波谱分析，分析了 DAP 制备的 PDOPT 和 Kumada 催化剂转移缩聚 (KCTP) 制备的 PDOPT 中存在的缺陷结构，以进行比较。由于附加苯环产生复杂的 1 H NMR 光谱，因此可以使用明确的低聚物和 13 C NMR 光谱来识别缺陷结构。对于最高分子量的 DAP 样品，我们发现了内部尾对尾缺陷 (TT) 的证据，而 KCTP 制造的 PDOPT 似乎在链端带有 TT 缺陷。内部 TT 缺陷降低了热转变和热函，导致等温结晶薄膜中产生更小、更不明确的球晶。这些结果表明，内部 TT 缺陷不会严重影响经过充分研究的聚（3-己基噻吩）类似物的结构形成，但在 PDOPT 中控制和消除更为重要，其中有序仅通过侧链结晶发生。
One property central to π-conjugated polymers is the ability of polymer backbones to interact intermolecularly through the direct contact of π-orbitals. Poly(3-(2,5-dioctylphenyl)thiophene) (PDOPT) is a remarkable exception as the bulky side chains prohibit main chain π–π interactions. However, due to side-chain crystallization of interdigitatedn-octyl side chains, PDOPT is semicrystalline, and thus any deviation from a perfect regioregularity can severely affect crystallization. Here, we synthesize PDOPT via direct arylation polycondensation (DAP) for the first time and analyze the effect of various reaction conditions on molecular weight, end groups, defect structures, crystallinity, and morphology. Despite extensive optimization of PDOPT synthesis via DAP including bulk polymerization, MW is limited toMn,SEC∼ 10 kg/mol as a result of dehalogenation of chain ends. Extensive NMR spectroscopy is carried out to analyze defect structures present in PDOPT made by DAP and also made by Kumada catalyst transfer polycondensation (KCTP) for comparison. Because of the complex1H NMR spectra arising from the additional phenyl rings, defect structures are identified using well-defined oligomers and13C NMR spectroscopy. For the highest MW DAP samples, we find evidence for internal tail-to-tail defects (TT), while PDOPT made by KCTP appears to carry a TT defect at the chain end. The internal TT defect lowers the thermal transitions and enthalpies and leads to smaller and less defined spherulites in isothermally crystallized thin films. These results suggest that internal TT defects, which do not severely affect structure formation in the well-studied poly(3-hexylthiophene) analog, are much more important to be controlled and eliminated in the case of PDOPT, in which ordering occurs exclusively by side-chain crystallization.
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影响因子：
5.5
作者：
Okamoto, Ken;Zhang, Junxiang;Luscombe, Christine K.
通讯作者：
Luscombe, Christine K.
影响因子：
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作者：
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通讯作者：
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通讯作者：
DeLongchamp, Dean M.
影响因子：
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