Le My Linh, Rawlings Dakota, Danielsen Scott P O, Kennard Rhiannon M, Chabinyc Michael L, Segalman Rachel A
Materials Department, University of California, Santa Barbara, California 93106, United States.
Chemical Engineering Department, University of California, Santa Barbara, California 93106, United States.
ACS Macro Lett. 2021 Aug 17;10(8):1008-1014. doi: 10.1021/acsmacrolett.1c00354. Epub 2021 Jul 20.
Conjugated polyelectrolytes (CPEs), which combine π-conjugated backbones with ionic side chains, are intrinsically soluble in polar solvents and have demonstrated tunability with respect to solution processability and optoelectronic performance. However, this class of polymers often suffers from limited solubility in water. Here, we demonstrate how polyelectrolyte coacervation can be utilized for aqueous processing of conjugated polymers at extremely high polymer loading. Sampling various mixing conditions, we identify compositions that enable the formation of complex coacervates of an alkoxysulfonate-substituted PEDOT (PEDOT-S) with poly(3-methyl-1-propylimidazolylacrylamide) (PA-MPI). The resulting coacervate is a viscous fluid containing 50% / polymer and can be readily blade-coated into films of 4 ± 0.5 μm thick. Subsequent acid doping of the film increased the electrical conductivity of the coacervate to twice that of a doped film of neat PEDOT-S. This higher conductivity of the doped coacervate film suggests an enhancement in charge carrier transport along PEDOT-S backbone, in agreement with spectroscopic data, which shows an enhancement in the conjugation length of PEDOT-S upon coacervation. This study illustrates the utilization of electrostatic interactions in aqueous processing of conjugated polymers, which will be useful in large-scale industrial processing of semiconductive materials using limited solvent and with added enhancements to optoelectronic properties.
共轭聚电解质（CPEs）将π共轭主链与离子侧链相结合，本质上可溶于极性溶剂，并在溶液可加工性和光电性能方面表现出可调性。然而，这类聚合物在水中的溶解度往往有限。在此，我们展示了如何利用聚电解质凝聚法在极高聚合物负载量下对共轭聚合物进行水性加工。通过对各种混合条件进行采样，我们确定了能够使烷氧基磺酸盐取代的聚3,4-乙撑二氧噻吩（PEDOT-S）与聚（3-甲基-1-丙基咪唑基丙烯酰胺）（PA-MPI）形成复合凝聚层的组成。所得凝聚层是一种含有50%聚合物的粘性流体，可轻松通过刮刀法制成4±0.5μm厚的薄膜。随后对薄膜进行酸掺杂，使凝聚层的电导率提高到纯PEDOT-S掺杂薄膜的两倍。掺杂凝聚层薄膜的这种较高电导率表明沿PEDOT-S主链的电荷载流子传输增强，这与光谱数据一致，光谱数据显示凝聚后PEDOT-S的共轭长度增加。这项研究说明了静电相互作用在共轭聚合物水性加工中的应用，这将有助于在使用有限溶剂并增强光电性能的情况下对半导体材料进行大规模工业加工。
