Associative Phase Separation of Aqueous π-Conjugated Polyelectrolytes Couples Photophysical and Mechanical Properties
Associative Phase Separation of Aqueous π-Conjugated Polyelectrolytes Couples Photophysical and Mechanical Properties
复制标题
DOI：
10.1021/acs.chemmater.0c02424
复制
发表时间：
2021-02-05
影响因子：
8.6
通讯作者：
Ayzner, Alexander L.
中科院分区：
文献类型：
--
作者：
Johnston, Anna R.;Perry, Sarah L.;Ayzner, Alexander L.
水溶性聚电解质的缔合相分离在食品科学、生物医学、材料科学和益生菌组织等许多不同的领域中都具有重要的意义。具体地说，导致相反电荷聚电解质复杂凝聚的缔合相分离已被广泛研究，以指导对合成电池模拟物的研究。然而，共轭聚电解质(CPE)，一种类似于捕光细胞器中发现的生色团的大分子，其相行为的研究还很少。系统地了解离子强度对CPE相行为的影响可以深入了解这些体系形成复杂凝聚体的可能性，并改进对这些材料的光物理性质的控制。本研究考察了三种简单盐(溴化锂、溴化钾和溴化铯)的离子强度(0-5.0M)的增加对阳离子CPE[聚(荧烯-对苯基)]和阴离子非共轭聚电解质[聚(4-苯乙烯磺酸)]络合物相行为的影响。发现无论盐的类型如何，缔合相分离成稀释的和浓缩的聚电解质相。我们报道了离子的相组成和离子类型对浓缩相的光物理性质的影响，发现反阳离子的性质控制着辐射衰减率和激子扩散动力学。此外，我们证明了富含聚合物的相能够招募非极性的、基于富勒烯的电子受体PC[70]BM，从而可能由于光诱导电子转移而导致光致发光猝灭。我们的发现表明，基于CPE的凝聚状相的形成是有希望的，并强调了络合物与不同极化率和大小的离子相互作用的重要性。此外，这些体系形成液体电子给体/受主体异质结的可能性对它们在光电子学中的应用具有重要的意义。
The associative phase separation of water-soluble polyelectrolytes is important across many different fields including food science, biomedicine, materials science, and prebiotic organization. Specifically, associative phase separation leading to complex coacervation of oppositely charged polyelectrolytes has been extensively studied to inform research into synthetic cell mimics. However, the phase behavior of conjugated polyelectrolytes (CPEs), macromolecules analogous to chromophores found in light harvesting organelles, has been investigated only minimally. A systematic understanding of the influence of ionic strength on the phase behavior of CPEs could provide insights into the potential for these systems to form complex coacervates and improve control over the photophysical properties of these materials. In this study, the influence of increasing ionic strength (0-5.0 M) of three simple salts (LiBr, KBr, and CsBr) on the phase behavior of a cationic CPE [poly(fluorene-alt-phenylene)] and an anionic non-conjugated polyelectrolyte [poly(4-styrenesulfonate)] complex is interrogated. Associative phase separation into diluted and concentrated polyelectrolyte phases was found to occur regardless of salt type. We report on the phase composition and influence of the ion type on the photophysical properties of the concentrated phase, where the nature of the counter cation was found to manipulate the radiative decay rate and the exciton diffusion dynamics. Additionally, we demonstrate the ability of the polymer-rich phase to recruit a nonpolar, fullerene-based electron acceptor PC[70]BM, resulting in photoluminescence quenching likely due to photoinduced electron transfer. Our findings show promise for the formation of CPE-based coacervate-like phases and highlight the importance of the interactions of the complex with ions differing in polarizability and size. Additionally, the potential for these systems to form liquid electron donor/acceptor bulk heterojunctions has great implications for their use in optoelectronics.