Combined role of regioregularity and molecular weight on melt-crystallization and self-nucleation of poly(3-hexylthiophene)
Combined role of regioregularity and molecular weight on melt-crystallization and self-nucleation of poly(3-hexylthiophene)
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DOI：
10.1016/j.polymer.2022.125341
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发表时间：
2022-09
期刊：
影响因子：
4.6
通讯作者：
Ramin Hosseinabad;Jesse Kuebler;Lucia Fernandez-Ballester
中科院分区：
文献类型：
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作者：
Ramin Hosseinabad;Jesse Kuebler;Lucia Fernandez-Ballester
共轭聚合物的熔融结晶作为溶液处理的一种环境友好的替代方法具有潜在的潜力，但分子属性和潜在的控制策略的具体作用在很大程度上仍未被探索。在这里，两个系列的区域规则聚(3-己基噻吩基)(P3HT)表明，链长的影响强烈地依赖于链缺陷的数量(区域规则)。在折叠链段以外，增加90%区域规则P3HT的相对分子质量会导致结晶动力学变慢，结晶的热稳定性降低，而95%区域规则会使结晶对链长几乎不敏感。熔融自晶种可以用来控制P3HT的结晶温度，但当结晶受阻最大时最有效--即对于更长、更有缺陷的链。P3HT自晶种是由原始微晶的热稳定性决定的，而不是仅依赖于分子量的扩散效应。总体而言，这些结果强调了控制和报告区域规律性和分子量的迫切需要。
Melt-crystallization of conjugated polymers has potential as an environmentally-friendly alternative to solution processing, but the specific role of molecular attributes and potential control strategies remain largely unexplored. Here, two series of regioregular poly(3-hexylthiophene) (P3HT) reveal that the effects of chain length depend strongly on the amount of chain defects (regioregularity). Beyond the chain-folding transition, increasing molecular weight Mwfor 90% regioregular P3HT results in slower crystallization kinetics and crystallites of reduced thermal stability, while 95% regioregularity renders crystallization nearly insensitive to chain length. Melt self-seeding can be used to manipulate the crystallization temperature of P3HT, but is most efficient when crystallization is hindered the most—i.e. for longer, more defective chains. P3HT self-seeding is dominated by the thermal stability of the crystallites originally present, and not by diffusion effects solely dependent on Mw. Overall, the results underscore the critical need to control and report both regioregularity and molecular weight.