Lo Chun-Yuan, Koutsoukos Kelsey P, Nguyen Dan My, Wu Yuhang, Angel Trujillo David Alejandro, Miller Tabitha, Shrestha Tulaja, Mackey Ethan, Damani Vidhika S, Kanbur Uddhav, Opila Robert, Martin David C, Kaphan David, Kayser Laure V
Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States.
Department of Materials Science and Engineering, University of Delaware, Newark, Delaware 19716, United States.
JACS Au. 2024 Jul 3;4(7):2596-2605. doi: 10.1021/jacsau.4c00355. eCollection 2024 Jul 22.
The accumulation of plastic waste in the environment is a growing environmental, economic, and societal challenge. Plastic upgrading, the conversion of low-value polymers to high-value materials, could address this challenge. Among upgrading strategies, the sulfonation of aromatic polymers is a powerful approach to access high-value materials for a range of applications, such as ion-exchange resins and membranes, electronic materials, and pharmaceuticals. While many sulfonation methods have been reported, achieving high degrees of sulfonation while minimizing side reactions that lead to defects in the polymer chains remains challenging. Additionally, sulfonating agents are most often used in large excess, which prevents precise control over the degree of sulfonation of aromatic polymers and their functionality. Herein, we address these challenges using 1,3-disulfonic acid imidazolium chloride ([Dsim]Cl), a sulfonic acid-based ionic liquid, to sulfonate aromatic polymers and upgrade plastic waste to electronic materials. We show that stoichiometric [Dsim]Cl can effectively sulfonate model polystyrene up to 92% in high yields, with minimal defects and high regioselectivity for the position. Owing to its high reactivity, the use of substoichiometric [Dsim]Cl uniquely allows for precise control over the degree of sulfonation of polystyrene. This approach is also applicable to a wide range of aromatic polymers, including waste plastic. To prove the utility of our approach, samples of poly(styrene sulfonate) (PSS), obtained from either partially sulfonated polystyrene or expanded polystyrene waste, are used as scaffolds for poly(3,4-ethylenedioxythiophene) (PEDOT) to form the ubiquitous conductive material PEDOT:PSS. PEDOT:PSS from plastic waste is subsequently integrated into organic electrochemical transistors (OECTs) or as a hole transport layer (HTL) in a hybrid solar cell and shows the same performance as commercial PEDOT:PSS. This imidazolium-mediated approach to precisely sulfonating aromatic polymers provides a pathway toward upgrading postconsumer plastic waste to high-value electronic materials.
环境中塑料废弃物的积累是一个日益严峻的环境、经济和社会挑战。塑料升级，即将低价值聚合物转化为高价值材料，有望应对这一挑战。在各种升级策略中，芳香族聚合物的磺化是一种有效的方法，可用于制备一系列高价值材料，如离子交换树脂和膜、电子材料以及药物。尽管已有许多磺化方法被报道，但在实现高磺化度的同时尽量减少导致聚合物链缺陷的副反应仍然具有挑战性。此外，磺化剂通常大量过量使用，这使得难以精确控制芳香族聚合物的磺化度及其功能。在此，我们使用1,3 - 二磺酸咪唑鎓氯化物（[Dsim]Cl），一种基于磺酸的离子液体，来解决这些挑战，将芳香族聚合物磺化并将塑料废弃物升级为电子材料。我们表明，化学计量的[Dsim]Cl能够以高产率有效地将模型聚苯乙烯磺化至92%，缺陷最少且对位具有高区域选择性。由于其高反应活性，使用亚化学计量的[Dsim]Cl能够独特地精确控制聚苯乙烯的磺化度。这种方法也适用于多种芳香族聚合物，包括废塑料。为了证明我们方法的实用性，从部分磺化的聚苯乙烯或发泡聚苯乙烯废料中获得的聚（苯乙烯磺酸盐）（PSS）样品被用作聚（3,4 - 乙撑二氧噻吩）（PEDOT）的支架，以形成广泛使用的导电材料PEDOT:PSS。随后，由塑料废料制成的PEDOT:PSS被集成到有机电化学晶体管（OECT）中或用作混合太阳能电池中的空穴传输层（HTL），并表现出与市售PEDOT:PSS相同的性能。这种咪唑鎓介导的精确磺化芳香族聚合物的方法为将消费后塑料废料升级为高价值电子材料提供了一条途径。
