Oh Saejin, Nikolaev Andrei, Tagami Kan, Tran Thi, Lee Dongwook, Mukherjee Sanjoy, Segalman Rachel A, Han Songi, Read de Alaniz Javier, Chabinyc Michael L
Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, California 93106, United States.
Department of Chemical Engineering, University of California, Santa Barbara, Santa Barbara, California 93106, United States.
ACS Appl Mater Interfaces. 2021 Feb 3;13(4):5319-5326. doi: 10.1021/acsami.0c20462. Epub 2021 Jan 22.
Polymers that are elastic while supporting charge transport are desirable for flexible and soft electronics. Many polymers with bulky and conjugated redox-active pendant units have high glass transition temperatures () in their neutral form that will not lead to elasticity at room temperature. Their behavior in charged form in the solid state without an electrolyte has not been extensively studied. Here, the design strategy of polymeric ionic liquid where two weakly interacting ionic groups are used to maintain a low is shown to lead to flexible redox active polymers. The use of a flexible ethylene backbone and redox-active phenothiazine (PTZ)-based pendant group resulted in polymers with relatively low that are electrically conductive. PTZ that was N-substituted with 2-(2-ethoxyethoxy)ethoxy)ethyl was found to promote solubility of the polymer and lower the of the neutral polymer by ∼150 °C relative to that of the of a variant without the N-substituent. Doping with trifluoromethanesulfonimide leads to an electrically conductive polymer without significantly increasing the . Physical characterization by UV-vis-NIR spectroscopy, electron spin resonance spectroscopy, and impedance spectroscopy verified that the molecular design leads to an efficient charge hopping between the PTZ groups.
对于柔性和软性电子器件而言，既具有弹性又能支持电荷传输的聚合物是理想的材料。许多带有庞大且共轭的氧化还原活性侧基单元的聚合物，其处于中性形式时具有较高的玻璃化转变温度（），这使得它们在室温下不会产生弹性。它们在无电解质的固态带电形式下的行为尚未得到广泛研究。在此，展示了一种聚合物离子液体的设计策略，即使用两个弱相互作用的离子基团来维持较低的 ，从而得到柔性氧化还原活性聚合物。使用柔性的乙烯主链和基于氧化还原活性吩噻嗪（PTZ）的侧基，得到了具有相对较低 且导电的聚合物。发现用2-(2-乙氧基乙氧基)乙氧基)乙基对PTZ进行N-取代可促进聚合物的溶解性，并使中性聚合物的 相对于无N-取代变体的 降低约150°C。用三氟甲磺酰亚胺进行掺杂可得到一种导电聚合物，而不会显著提高 。通过紫外-可见-近红外光谱、电子自旋共振光谱和阻抗光谱进行的物理表征证实，这种分子设计导致PTZ基团之间实现了有效的电荷跳跃。
