Macromolecules最新文献_第8页

Atomic-Scale Imaging of Condensed Counterions 凝聚反离子的原子级成像

IF 5.5 1区化学 Q1 POLYMER SCIENCE

Macromolecules

Pub Date : 2024-10-25 DOI: 10.1021/acs.macromol.4c01417

Morgan Seidler, Tianyi Yu, Xubo Luo, David Prendergast, Ronald N. Zuckermann, Xi Jiang, Nitash P. Balsara

The functioning of a wide variety of charged macromolecules, from DNA to fuel cell membranes, is dependent on how the counterions surrounding them are arranged. In order to decrease Coulombic repulsion, some of the fixed charges on these molecules are neutralized by a fraction of the counterions─this phenomenon is called counterion condensation. The nature of counterion condensation can be only be inferred indirectly from traditional experiments such as X-ray scattering and modern experiments such as single molecule electrometry. The prevalent conclusion in the literature, based on both theory and experiment, is that the distribution of counterions is peaked right next to the macromolecule, i.e., condensation results in the formation of contact ion pairs. In this study, cryogenic electron microscopy (cryo-EM) was used to study the arrangement of condensed halide counterions near a positively charged polypeptoid nanofiber. The locations of both condensed and fixed charges were determined directly from atomic-scale images. Our experimentally determined counterion distributions were peaked at distances of about 5 Å away from the fixed positive charge, indicating the presence of a layer of water molecules between condensed ion pairs. We posit that this distribution is driven by the entropy of the condensed ions.

从 DNA 到燃料细胞膜，各种带电大分子的功能都取决于其周围反离子的排列方式。为了减少库仑斥力，这些分子上的部分固定电荷会被一部分反离子中和--这种现象被称为反离子凝聚。反离子凝聚的性质只能通过 X 射线散射等传统实验和单分子电学等现代实验来间接推断。文献中基于理论和实验得出的普遍结论是，反离子的分布在大分子旁边达到峰值，即凝聚的结果是形成接触离子对。本研究利用低温电子显微镜（cryo-EM）研究了带正电荷的多肽基纳米纤维附近缩合卤化物反离子的排列。凝聚电荷和固定电荷的位置都是直接通过原子尺度图像确定的。我们通过实验确定的反离子分布在距离固定正电荷约 5 Å 处达到峰值，表明在凝聚离子对之间存在一层水分子。我们认为这种分布是由凝聚离子的熵驱动的。

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引用次数: 0

Incorporation of Thioacetate Pendants on a Polyalkenamer Enables High Extensibility 在聚烯酰胺上加入硫代乙酸酯基团可实现高延展性

IF 5.5 1区化学 Q1 POLYMER SCIENCE

Macromolecules

Pub Date : 2024-10-24 DOI: 10.1021/acs.macromol.4c02110

Roshni John Chethalen, Myounguk Kim, Juan Correa Ruiz, Chien-Hua Tu, Jordan Gray, Karen I. Winey, Alan J. Lesser, Alfred J. Crosby, E. Bryan Coughlin

This study focuses on functionalizing polycyclooctene (PCOE) with thioacetate groups using thiol–ene click chemistry. The ethylene thioacetate (EVSA) copolymers produced vary in thioacetate incorporation (4–25 mol %) via a controlled semibatch addition technique with AIBN dosing. Copolymers with 4–14 mol % thioacetate are semicrystalline, while those with 20–25 mol % are amorphous. Increased functionalization correlates with decreased crystallinity and increased stretchability, with the highest functionalization (25 mol %) showing a modulus of 0.045 MPa and 2000% elongation at break. This behavior is due to the pseudoprecise functionalization of the thioacetate pendants and intrinsic cross-linking that occurs during melt processing. Broadband dielectric spectroscopy (BDS) indicates a low activation energy barrier (16 kJ/mol for the β process), suggesting potential self-healing applications.

本研究的重点是利用硫醇-烯点击化学将聚环辛烯（PCOE）与硫代乙酸酯基团官能化。通过使用 AIBN 配料的受控半批次添加技术，生产出的硫代乙酸乙烯酯 (EVSA) 共聚物的硫代乙酸乙烯酯含量（4-25 摩尔%）各不相同。硫代乙酸酯含量为 4-14 摩尔%的共聚物为半结晶，而含量为 20-25 摩尔%的共聚物为无定形。官能度的增加与结晶度的降低和拉伸性的增加有关，官能度最高的聚合物（25 摩尔%）的模量为 0.045 兆帕，断裂伸长率为 2000%。这种行为是由于硫代乙酸酯垂饰的假精确官能化和熔融加工过程中发生的内在交联。宽带介电光谱（BDS）显示，其活化能势垒较低（β 过程为 16 kJ/mol），这表明它具有潜在的自愈合应用价值。

引用次数: 0

Wetting-Induced Elastocapillary Deformation of Supported Thin Rubbery Polymer Films 湿润诱导的支撑型薄橡胶聚合物薄膜的弹力毛细管变形

IF 5.5 1区化学 Q1 POLYMER SCIENCE

Macromolecules

Pub Date : 2024-10-24 DOI: 10.1021/acs.macromol.4c01784

Qing Wang, Wenbo Wang, Cheng Wu, Jintian Luo, Jiajia Zhou, Biao Zuo

Whereas classical surface chemistry holds that capillarity controls fluid behavior, recent investigations indicate that it also dominates the mechanics of soft solids at scales below the elastocapillary length (l_e), which is the ratio of surface tension γ of liquid to elastic modulus E of the solid. We used atomic force microscopy to probe elastocapillary deformations induced by droplets of various radii (R) on partially wetting rubbery films of entangled polymers possessing thicknesses down to 230 nm. The transition from elasticity to capillarity dominated deformation with decreasing R values is visualized with high spatial resolution. The elasticity-to-capillarity transition shifted to lower R values, when the film thickness (h) is reduced to a threshold below approximately 10 times of the bulk l_e (l_e,bulk) values, indicative of a smaller l_e on the thin films. This enabled the identification of a thickness-dependent elastocapillary length (l_e,h) ∼ (h³γ/E)^1/4 for soft polymer films on rigid substrates, and, by extension, suggests the scaling l_e,h ∼ h^–n, where n varies with the contrast between the moduli of the films and substrates. The results resolve the foundation of the fluid wetting and interactions with thin, substrate-supported soft films.

经典的表面化学认为毛细管控制着流体行为，而最近的研究表明，在低于弹性毛细管长度（即液体表面张力γ与固体弹性模量E之比）的尺度上，毛细管也主导着软固体的力学。我们使用原子力显微镜探测了不同半径（R）的液滴在厚度低至 230 纳米的缠结聚合物部分润湿橡胶薄膜上引起的弹性毛细管变形。随着 R 值的减小，从弹性变形到毛细管主导变形的转变是以高空间分辨率可视化的。当薄膜厚度（h）减小到低于体积le（le,bulk）值约 10 倍的临界值时，弹性向毛细管的转变就会转向较低的 R 值，这表明薄膜上的le 值较小。这就确定了刚性基底上的软质聚合物薄膜随厚度变化的弹性毛细管长度 (le,h) ∼ (h3γ/E)1/4，并由此推导出比例 le,h ∼ h-n，其中 n 随薄膜和基底的模量对比而变化。这些结果解决了流体润湿以及与基底支撑的软薄膜相互作用的基础问题。

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引用次数: 0

Nonmonotonic Impact of Statistical Copolymer Composition on the Kinetics of Capillary Rise Infiltration 统计共聚物成分对毛细管上升渗透动力学的非单调影响

IF 5.5 1区化学 Q1 POLYMER SCIENCE

Macromolecules

Pub Date : 2024-10-24 DOI: 10.1021/acs.macromol.4c01708

Tae-Young Heo, Théophile Ienn, Julien Bernard, Robert A. Riggleman, Daeyeon Lee

Infiltration dynamics of poly(styrene-stat-2-vinylpyridine) (PS-stat-P2VP) statistical copolymers (StCPs) undergoing capillary rise infiltration into the interstices of silica nanoparticle (SiO₂ NP) packings are investigated by in situ spectroscopic ellipsometry with varying ratios of strongly interacting 2-vinylpyridine (2VP) and weakly interacting styrene (S) repeat units. As the fraction of 2VP (f_P2VP) increases, a nonmonotonic dependence is observed in the time required to fully fill the interstices of the SiO₂ NP packings (t_inf) and the effective viscosity (η_eff). To understand the mechanism behind the nonmonotonic trend in infiltration dynamics, polymer properties such as zero-shear viscosity (η₀) and glass transition temperature (T_g) are considered; however, these factors fail to explain the trend. When the strong interactions between 2VP and SiO₂ are suppressed by modifying the surface of SiO₂ NPs with the epoxide group, the infiltration dynamics no longer show strong dependence on f_P2VP. This result indicates the important role played by the 2VP unit in the anomalous slowdown observed in StCPs, possibly by controlling its conformation on the pore surface and the interactions between the surface-adsorbed chains and chains that are translated through the pores.

通过原位光谱椭偏仪研究了聚苯乙烯-苯乙烯-2-吡啶（PS-stat-P2VP）统计共聚物（StCPs）在二氧化硅纳米粒子（SiO2 NP）填料的间隙中进行毛细管上升渗透时的渗透动力学，2-乙烯基吡啶（2VP）强相互作用和苯乙烯（S）弱相互作用重复单元的比例各不相同。随着 2VP 部分（fP2VP）的增加，完全填充 SiO2 NP 填料间隙所需的时间（tinf）和有效粘度（ηeff）出现了非单调依赖性。为了了解渗透动力学非单调趋势背后的机制，我们考虑了零剪切粘度 (η0) 和玻璃化转变温度 (Tg) 等聚合物特性；然而，这些因素无法解释这一趋势。当通过环氧基团修饰 SiO2 NPs 表面来抑制 2VP 与 SiO2 之间的强相互作用时，渗透动力学不再显示出对 fP2VP 的强烈依赖性。这一结果表明，2VP 单元在 StCPs 中观察到的异常减速中发挥了重要作用，可能是通过控制其在孔隙表面的构象以及表面吸附链与通过孔隙平移的链之间的相互作用。

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引用次数: 0

The Biosynthesis and Applications of Protein Lipidation 蛋白质脂化的生物合成与应用

IF 51.4 1区化学 Q1 POLYMER SCIENCE

Macromolecules

Pub Date : 2024-10-23 DOI: 10.1021/acs.chemrev.4c0041910.1021/acs.chemrev.4c00419

Wenlong Ding, Jiayu Gu, Wenyuan Xu, Jing Wu, Yiwen Huang, Shuai Zhang* and Shixian Lin*,

Protein lipidation dramatically affects protein structure, localization, and trafficking via remodeling protein–membrane and protein–protein interactions through hydrophobic lipid moieties. Understanding the biosynthesis of lipidated proteins, whether natural ones or mimetics, is crucial for reconstructing, validating, and studying the molecular mechanisms and biological functions of protein lipidation. In this Perspective, we first provide an overview of the natural enzymatic biosynthetic pathways of protein lipidation in mammalian cells, focusing on the enzymatic machineries and their chemical linkages. We then discuss strategies to biosynthesize protein lipidation in mammalian cells by engineering modification machineries and substrates. Additionally, we explore site-specific protein lipidation biosynthesis in vitro via enzyme-mediated ligations and in vivo primarily through genetic code expansion strategies. We also discuss the use of small molecule tools to modulate the process of protein lipidation biosynthesis. Finally, we provide concluding remarks and discuss future directions for the biosynthesis and applications of protein lipidation.

蛋白质脂化通过疏水性脂质分子重塑蛋白质-膜和蛋白质-蛋白质之间的相互作用，从而极大地影响蛋白质的结构、定位和运输。了解脂化蛋白（无论是天然脂化蛋白还是模拟蛋白）的生物合成，对于重建、验证和研究蛋白质脂化的分子机制和生物学功能至关重要。在本《视角》中，我们首先概述了哺乳动物细胞中蛋白质脂化的天然酶生物合成途径，重点介绍了酶机制及其化学联系。然后，我们讨论了通过工程改造机制和底物在哺乳动物细胞中生物合成蛋白质脂质化的策略。此外，我们还探讨了体外通过酶介导的连接和体内主要通过遗传密码扩增策略进行的特定位点蛋白质脂化生物合成。我们还讨论了使用小分子工具调节蛋白质脂化生物合成过程的问题。最后，我们提出了结束语，并讨论了蛋白质脂化的生物合成和应用的未来方向。

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引用次数: 0

Coherence in Chemistry: Foundations and Frontiers 化学中的相干性：基础与前沿

IF 51.4 1区化学 Q1 POLYMER SCIENCE

Macromolecules

Pub Date : 2024-10-23 DOI: 10.1021/acs.chemrev.3c0064310.1021/acs.chemrev.3c00643

Jonathan D. Schultz*, Jonathon L. Yuly*, Eric A. Arsenault, Kelsey Parker, Sutirtha N. Chowdhury, Reshmi Dani, Sohang Kundu, Hanggai Nuomin, Zhendian Zhang, Jesús Valdiviezo, Peng Zhang, Kaydren Orcutt, Seogjoo J. Jang, Graham R. Fleming, Nancy Makri, Jennifer P. Ogilvie, Michael J. Therien, Michael R. Wasielewski and David N. Beratan*,

Coherence refers to correlations in waves. Because matter has a wave-particle nature, it is unsurprising that coherence has deep connections with the most contemporary issues in chemistry research (e.g., energy harvesting, femtosecond spectroscopy, molecular qubits and more). But what does the word “coherence” really mean in the context of molecules and other quantum systems? We provide a review of key concepts, definitions, and methodologies, surrounding coherence phenomena in chemistry, and we describe how the terms “coherence” and “quantum coherence” refer to many different phenomena in chemistry. Moreover, we show how these notions are related to the concept of an interference pattern. Coherence phenomena are indeed complex, and ambiguous definitions may spawn confusion. By describing the many definitions and contexts for coherence in the molecular sciences, we aim to enhance understanding and communication in this broad and active area of chemistry.

相干指的是波的相关性。由于物质具有波粒共振的性质，相干性与化学研究中最现代的问题（如能量收集、飞秒光谱学、分子量子比特等）有着深刻的联系也就不足为奇了。但是，在分子和其他量子系统中，"相干性 "一词究竟意味着什么？我们回顾了围绕化学中相干现象的关键概念、定义和方法，并描述了 "相干 "和 "量子相干 "如何指代化学中的许多不同现象。此外，我们还展示了这些概念与干涉模式概念之间的关系。相干现象的确很复杂，模糊的定义可能会造成混淆。通过描述分子科学中相干的多种定义和背景，我们希望增进对这一广泛而活跃的化学领域的理解和交流。

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引用次数: 0

Oxidative Upcycling of Polyolefin Wastes into the Dynamically Cross-Linked Elastomer 将聚烯烃废料氧化升级再循环为动态交联弹性体

IF 5.5 1区化学 Q1 POLYMER SCIENCE

Macromolecules

Pub Date : 2024-10-23 DOI: 10.1021/acs.macromol.4c01869

Yinlong Chang, Yangke Xiao, Minghao Sun, Weiqiang Gao, Liqian Zhu, Qingyue Wang, Wen-Jun Wang, Bo-Geng Li, Pingwei Liu

Oxidative cracking of polyolefins into functionalized molecules or oligomers promises the chemical upcycling of plastic wastes. In this work, we develop a novel approach to polyolefin waste upcycling that utilizes low-temperature oxidative cracking combined with dynamic cross-linking to produce recyclable elastomers. High-density polyethylene is oxidized into functionalized oligomers with end carboxyl groups at 110 °C, achieving tunable number-average molecular weights (M_n) ranging from 1500 to 5500 Da at distributions (D̵) between 2.91 and 3.33. These oligomers with high crystallinity directly react with amorphous cis-polybutadiene containing pendant epoxy groups (an oxidized product of cis-polybutadiene) through esterification, forming a dynamically cross-linked elastomer. The elastomer displays a low glass transition temperature (T_g) of approximately −100 °C while maintaining a melting point (T_m) above 80 °C; it showcases a Young′s modulus (E) of 12.0 ± 0.4 MPa, elongation at break (ε) of 600 ± 28%, tensile strength (σ) of 16.4 ± 0.8 MPa, tensile toughness (U_T) of 46.0 ± 3.5 MJ·m^–3, and a good elasticity with 81.8% elastic recovery in a 10-cycle tensile test, even higher than that of commercial POEs such as POE-8150 of Dow Company. The dynamic ester-bond-based cross-linking enables the elastomer to be reprocessed. Our study introduces an efficient chemical upcycling process for polyolefin wastes, eliminating the need for tedious separation steps of cracking products.

将聚烯烃氧化裂解成功能化分子或低聚物有望实现塑料废物的化学升级再循环。在这项工作中，我们开发了一种新的聚烯烃废物升级再循环方法，利用低温氧化裂解结合动态交联来生产可回收的弹性体。高密度聚乙烯在 110 °C 下被氧化成带有末端羧基的官能化低聚物，在分布 (D̵) 介于 2.91 和 3.33 之间时，可获得 1500 到 5500 Da 的可调数均分子量 (Mn)。这些具有高结晶度的低聚物通过酯化作用直接与含有悬垂环氧基团（顺式聚丁二烯的氧化产物）的无定形顺式聚丁二烯发生反应，形成动态交联弹性体。这种弹性体的玻璃化转变温度（Tg）较低，约为 -100 °C，同时熔点（Tm）保持在 80 °C 以上；它的杨氏模量（E）为 12.0 ± 0.4 MPa，断裂伸长率（ε）为 600 ± 28%，拉伸强度（σ）为 16.拉伸强度（σ）为 16.4 ± 0.8 MPa，拉伸韧性（UT）为 46.0 ± 3.5 MJ-m-3，弹性良好，在 10 周期拉伸试验中的弹性恢复率为 81.8%，甚至高于陶氏公司的 POE-8150 等商用 POE。基于动态酯键的交联使这种弹性体可以进行再加工。我们的研究为聚烯烃废料引入了一种高效的化学升级再循环工艺，省去了繁琐的裂解产品分离步骤。

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引用次数: 0

Stretching and Bending Moduli of Bilayer Films Inferred from Wrinkle Patterns 从皱纹图案推断双层薄膜的拉伸和弯曲模量

IF 5.5 1区化学 Q1 POLYMER SCIENCE

Macromolecules

Pub Date : 2024-10-23 DOI: 10.1021/acs.macromol.4c01540

Jooyoung Chang, Narayanan Menon, Thomas P. Russell

Wrinkling patterns were used to investigate the mechanical properties of thin poly(styrene) (PS)/poly(methyl methacrylate) (PMMA) and PS/gold (Au) bilayer films. Films were floated on water with a water drop on the surface to induce wrinkling. The thicknesses and thickness ratios of the films were varied over a broad range. The PS/PMMA bilayer was chosen to provide a contrast in wetting properties, with equilibrium contact angles of θ_PMMA = 68° and θ_PS = 88° with water. The PS/Au bilayer was chosen to provide a large contrast in Young’s moduli, E_Au = 72 GPa and E_PS = 3.4 GPa. The stretching (Y) and bending (B) moduli of the bilayer films were obtained from measurements of the length and number of wrinkles in the wrinkle patterns. The experimentally derived values of Y and B were in reasonable agreement with the values computed from the bulk Young’s moduli and the thicknesses of the two components in the bilayer. The values of Y and B did not depend on which face of the film was exposed to the water droplet or bath when the capillary stresses were considered. Thus, finite size effects from the film thicknesses were unimportant over the range of thicknesses studied, and no relative displacement of the films was found, with the films remaining well-bonded even with deformation associated with wrinkling.

皱纹图案用于研究聚苯乙烯（PS）/聚甲基丙烯酸甲酯（PMMA）和聚苯乙烯/金（Au）双层薄膜的机械特性。薄膜漂浮在水面上，表面上有水滴诱发起皱。薄膜的厚度和厚度比在很大范围内变化。选择 PS/PMMA 双层膜是为了提供润湿性能的对比，其与水的平衡接触角分别为 θPMMA = 68° 和 θPS = 88°。选择 PS/Au 双层膜是为了提供较大的杨氏模量对比：EAu = 72 GPa 和 EPS = 3.4 GPa。双层薄膜的拉伸（Y）和弯曲（B）模量是通过测量皱纹图案中皱纹的长度和数量获得的。实验得出的 Y 值和 B 值与根据双层膜中两种成分的体杨氏模量和厚度计算得出的值基本一致。在考虑毛细应力时，Y 和 B 的值并不取决于薄膜的哪一面暴露在水滴或水浴中。因此，在所研究的薄膜厚度范围内，薄膜厚度的有限尺寸效应并不重要，也没有发现薄膜的相对位移，即使发生与起皱有关的变形，薄膜也能保持良好的粘结性。

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引用次数: 0

Topological Design and Mechanical Manipulation of Matrix-Free Polymer Grafted Nanoparticles Driven by Bond Exchanging 由键交换驱动的无基质聚合物接枝纳米粒子的拓扑设计与机械操控

IF 5.5 1区化学 Q1 POLYMER SCIENCE

Macromolecules

Pub Date : 2024-10-23 DOI: 10.1021/acs.macromol.4c01849

Qionghai Chen, Wanhui Huang, Liqun Zhang, Venkat Ganesan, Jun Liu

Tailoring mechanical properties through bond exchange reactions (BERs) demands precise topological manipulation, yet accurately correlating structures and properties to complex topologies remains a challenge. This investigation delves into matrix-free polymer grafted nanoparticles (PGNPs) with dynamic covalent bonds and examines how topological control can modulate material properties. Through coarse–grained molecular dynamics simulations, the alterations in the grafted polymer uniformity (α) induced by BERs triggered by terminals of grafted polymers are examined. Innovative α-kinetics theoretical model is proposed to capture the temporal evolution of topologies and elucidate the significant influence of BER kinetics and initial topology. Additionally, the α-equilibrium theoretical model characterizes equilibrium topologies, revealing the geometric distribution of grafted polymers. The theoretical models are further extended to include scenarios beyond terminal-triggered BERs, affirming their comprehensive applicability. Subsequently, it is elucidated how specific topological configurations can significantly enhance toughness and reveal the intrinsic mechanisms, which enable the construction of structure–property relationships. In summary, this study not only addresses the experimental challenges in the topological characterization of PGNPs, but also underscores the importance of strategic topological design in determining material properties and advancing material science.

通过键交换反应（BERs）定制机械性能需要精确的拓扑操作，但将结构和性能与复杂的拓扑结构准确关联起来仍是一项挑战。本研究深入研究了具有动态共价键的无基质聚合物接枝纳米粒子（PGNPs），并探讨了拓扑控制如何调节材料特性。通过粗粒度分子动力学模拟，研究了由接枝聚合物终端引发的误码分解所引起的接枝聚合物均匀性（α）的变化。提出了创新的 α 动力学理论模型，以捕捉拓扑结构的时间演化，并阐明 BER 动力学和初始拓扑结构的重要影响。此外，α 平衡理论模型还描述了平衡拓扑结构，揭示了接枝聚合物的几何分布。这些理论模型进一步扩展到终端触发的误码率以外的情况，从而肯定了它们的全面适用性。随后，研究阐明了特定拓扑结构如何显著提高韧性，并揭示了其内在机制，从而构建了结构-性能关系。总之，这项研究不仅解决了 PGNPs 拓扑表征中的实验难题，还强调了战略性拓扑设计在确定材料特性和推动材料科学发展方面的重要性。

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引用次数: 0

New Multiblock Copolymers Containing Quaternary Ammonium Groups with Ultramicroporous Structure for High-Temperature Proton Exchange Membrane Fuel Cells 用于高温质子交换膜燃料电池的具有超微孔结构的含季铵基的新型多嵌段共聚物

IF 5.5 1区化学 Q1 POLYMER SCIENCE

Macromolecules

Pub Date : 2024-10-23 DOI: 10.1021/acs.macromol.4c02047

Binghui Liu, Qian Liu, Yang Pang, Tong Mu, Chengji Zhao

Polybenzimidazole (PBI) exhibits considerable advantages as a leading membrane material for high-temperature proton exchange membrane fuel cells (HT-PEMFCs). However, their harsh synthesis conditions and high processing costs have greatly restricted the large-scale commercialization of HT-PEMFCs. Therefore, developing high-performance and durable membrane materials as alternatives to PBI has been recognized as the key technical challenge for the advancement of HT-PEMFC technology. In this study, a series of novel multiblock copolymers QPSBI-b-xTMA, consisting of acidophobic pentafluorophenyl, acidophilic quaternary ammonium groups, and high free-volume spirobisindane, were synthesized by a straightforward polymerization process involving two kinds of low-molecular-weight oligomers with different structures. The resulting multiblock membranes QPSBI-b-xTMA demonstrate well-defined microporous properties, and the PA-doped membranes exhibit a microphase separation structure, which effectively facilitates proton conduction (75.45 mS cm^–1@200 °C). The HT-PEMFCs based on the QPSBI-b-xTMA/PA membrane can operate efficiently within the temperature range of 160–220 °C, achieving a high peak power density of 0.84 W cm^–2 without external pressure and humidity. Notably, owing to the siphoning effect of the micropores and the strong quaternary ammonium-biphosphate ion pairs, the fuel cell exhibits a stable performance at a high current density of 0.5 A cm^–2 at 160 °C, with a minimal voltage degradation rate of merely 4.7 μV h^–1. Thus, the newly developed QPSBI-b-xTMA/PA materials present a promising avenue for HT-PEMFC applications.

作为高温质子交换膜燃料电池（HT-PEMFCs）的主要膜材料，聚苯并咪唑（PBI）具有相当大的优势。然而，其苛刻的合成条件和高昂的加工成本极大地限制了高温质子交换膜燃料电池的大规模商业化。因此，开发高性能、耐用的膜材料作为 PBI 的替代品已被认为是 HT-PEMFC 技术发展的关键技术挑战。本研究通过两种不同结构的低分子量低聚物的直接聚合过程，合成了一系列新型多嵌段共聚物 QPSBI-b-xTMA，它们由疏酸性五氟苯基、亲酸性季铵基团和高自由体积螺双茚满组成。得到的多嵌段膜 QPSBI-b-xTMA 具有明确的微孔特性，掺杂 PA 的膜呈现出微相分离结构，可有效促进质子传导（75.45 mS cm-1@200 °C）。基于 QPSBI-b-xTMA/PA 膜的 HT-PEMFC 可在 160-220 °C 的温度范围内高效运行，在无外部压力和湿度的情况下达到 0.84 W cm-2 的峰值功率密度。值得注意的是，由于微孔的虹吸效应和强季铵-双磷酸离子对，该燃料电池在 160 ℃ 的高电流密度（0.5 A cm-2）下表现出稳定的性能，电压衰减率极低，仅为 4.7 μV h-1。因此，新开发的 QPSBI-b-xTMA/PA 材料为 HT-PEMFC 的应用提供了一条前景广阔的途径。

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引用次数: 0