Das Pratyusha, Zele Alexandra, Lin Ming-Pei, Mefford J Tyler, Chabinyc Michael L, Segalman Rachel A
Materials Research Laboratory, University of California, Santa Barbara, California 93106, United States.
Materials Department, University of California, Santa Barbara, California 93106, United States.
ACS Macro Lett. 2025 Jul 15;14(7):925-932. doi: 10.1021/acsmacrolett.5c00305. Epub 2025 Jun 16.
Conjugated polyelectrolyte complexes formed by the electrostatic compatibilization between a conjugated and an insulating polyelectrolyte are a versatile design platform for highly processable, high performing polymeric mixed ion-electron conductors. While electrostatic mediation in complexes allows for structure and property control, a fundamental understanding of how the properties of the constituent conjugated polyelectrolyte (CPE) translate to the resulting complex performance is necessary for future designs. To investigate the role of CPE architecture on the overall charge transport properties of the resulting complex properties, here we compare a water-soluble cationic poly(alkoxythiophene) derivative based on poly(3-alkoxy-4-methylthiophene) with an imidazolium pendant unit and bromide counterion to an analogous complex with poly(sodium 4-styrenesulfonate). Through spectroscopic, morphological, electrochemical, and charge transport characterization, we find that poly(alkoxythiophene)-based complexes exhibit high mixed conductivity, enhanced electrochemical stability, improved doping efficiency, and lower oxidation potential, relative to previously reported poly(3-alkylthiophene)-based complexes, making them more suitable candidates for electrochemical applications. Importantly, both CPE and complex films based on the poly(3-alkoxy-4-methylthiophene) chemistry display electronic conductivities on the order of 10-10 S/cm and impressive ionic conductivities up to the order of 10 S/cm, despite the ordered morphology of the 3-alkoxy-4-methylthiophene backbone. We make a key observation that the enhancement of the electronic conductivity of the CPE from an alkyl to alkoxythiophene backbone does not necessarily improve the electronic conduction of the resulting complex as observed in previous reports, thereby underscoring the role of complexation thermodynamics, dielectric strength of the electrostatic complex, and complex morphology on mixed conduction. This study provides fundamental insights governing future design rules of mixed-conducting polyelectrolyte complexes for next-generation energy applications.
由共轭聚电解质与绝缘聚电解质之间的静电增容作用形成的共轭聚电解质复合物，是一种用于制备具有高加工性、高性能的聚合物混合离子-电子导体的通用设计平台。虽然复合物中的静电介导作用能够实现结构和性能的调控，但要进行未来的设计，有必要从根本上理解构成共轭聚电解质（CPE）的性质如何转化为最终复合物的性能。为了研究CPE结构对所得复合物整体电荷传输性质的作用，在此我们将一种基于聚（3-烷氧基-4-甲基噻吩）且带有咪唑鎓侧基单元和溴化物抗衡离子的水溶性阳离子聚（烷氧基噻吩）衍生物与一种含有聚（4-苯乙烯磺酸钠）的类似复合物进行比较。通过光谱、形态、电化学和电荷传输表征，我们发现相对于先前报道的基于聚（3-烷基噻吩）的复合物，基于聚（烷氧基噻吩）的复合物表现出高混合电导率、增强的电化学稳定性、提高的掺杂效率以及更低的氧化电位，使其更适合作为电化学应用的候选材料。重要的是，基于聚（3-烷氧基-4-甲基噻吩）化学结构的CPE和复合物薄膜均显示出约10⁻¹⁰ S/cm量级的电子电导率以及高达10⁻³ S/cm量级的令人印象深刻的离子电导率，尽管3-烷氧基-4-甲基噻吩主链具有有序形态。我们得出一个关键观察结果，即如先前报道中所观察到的，CPE从烷基主链到烷氧基噻吩主链的电子电导率增强并不一定会提高所得复合物的电子传导性，从而强调了络合热力学、静电复合物的介电强度以及复合物形态对混合传导的作用。这项研究为下一代能源应用中混合导电聚电解质复合物的未来设计规则提供了基本见解。
