Side Chain Effects on the Conductivity of Phenothiazine-Derived Polyaniline
Side Chain Effects on the Conductivity of Phenothiazine-Derived Polyaniline
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DOI：
10.1021/acs.chemmater.3c02268
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发表时间：
2024-02-27
影响因子：
8.6
通讯作者：
Scott，Colleen N.
中科院分区：
文献类型：
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作者：
Giri，Hari;Ma，Guorong;Scott，Colleen N.
侧链烷基已成为将增溶基团纳入共轭聚合物的标准。然而，烷基的种类和它们在聚合物主链上的位置可以以许多不同的方式影响聚合物链的堆积，从而导致聚合物中许多不同的形态，从而影响其性质和性能。在本文中，我们研究了9种含吩噻嗪的聚苯胺衍生物（P1-P9）在吩噻嗪核心上具有烷基或芳基侧链，同时改变对苯二胺单元上甲基的数量对其电导率的影响。采用1H核磁共振波谱、紫外可见波谱、差示扫描量热法、扫描电镜、原子力显微镜、广角x射线散射（WAXS）等技术对聚合物的结构、物性、热性和形貌进行了研究。吩噻嗪核心上的丁基苯基取代基似乎在聚合物的骨架上提供了更大的刚性，从而导致系列3具有更高的tg，而包含2-己基癸基取代聚合物的系列2具有最低的tg，这归因于侧链的大体积，这限制了链间的相互作用。因此，系列2的电导率最低。然而，对电导率影响最大的是PPDA单元上的四甲基，由于聚合物主链的扭转应变（扭转），导致每个系列的电导率最低。WAXS数据显示主要是无定形薄膜；因此，这些材料的电导率似乎是由发生在非晶共轭材料中的多尺度电荷输运现象所控制的。我们的研究结果将有助于理解聚苯胺衍生物的侧链工程，以获得最佳性能。
Side chain alkyl groups have become the standard for incorporating solubilizing groups into conjugated polymers. However, the variety of alkyl groups available and their location on the polymer’s backbone can contribute to the packing of the polymer chains in many different ways, resulting in many different morphologies in the polymer that can affect its properties and performances. In this paper, we investigate the effects on the conductivity of nine phenothiazine-containing polyaniline derivatives (P1–P9) with alkyl or aryl side chains on the phenothiazine core while also varying the number of methyl groups on thep-phenylenediamine unit.1H nuclear magnetic resonance spectroscopy, ultraviolet–visible spectroscopy, differential scanning calorimetry, scanning electron microscopy, atomic force microscopy, and wide-angle X-ray scattering (WAXS) were all used to study the polymers’ structures, physical and thermal properties, and morphologies. Thet-butylphenyl substituent on the phenothiazine core seems to provide more rigidity in the polymer’s backbone resulting in higherTgfor series 3, while series 2 containing the 2-hexyldecyl-substituted polymers had the lowestTg, which is attributed to the large volume of the side chain, that limits interchain interactions. Consequently, series 2 had the lowest conductivity. However, the strongest effect on the conductivity was seen from the tetramethyl groups on the PPDA unit, which resulted in the lowest conductivity in each series due to torsional strain (twisting) in the polymer’s backbone. The WAXS data suggest mostly amorphous films; thus, the conductivity in these materials seems to be dominated by a multiscale charge transport phenomenon that occurs in amorphous conjugated materials. Our results will aid in the understanding of side chain engineering of PANI derivatives for their optimum performances.