聚丙烯酸盐在乙醇-水与电解液中构象和传输性能的分子模拟  

Molecular Simulations of Conformation and Ion-transport Performance of Polyacrylate in Ethanol-water and Electrolyte

作　　者：龚子洋 李炜乐 周仁杰 胡继文[1,2] 桂雪峰 韩亚芳 刘洋 黎伟欣 GONG Ziyang;LI Weile;ZHOU Renjie;HU Jiwen;GUI Xuefeng;HAN Yafang;LIU Yang;LI Weixin(Guangzhou Institute of Chemistry,Chinese Academy of Sciences,CAS Engineering Laboratory for Special Fine Chemicals,Guangzhou 510650,China;Management Committee of Shaoguan NanXiong Hi-teac Industry Development Zone,CASH GCC Shaoguan Research Institute of Advanced Materials,Nanxiong 512400,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院广州化学研究所中国科学院新型特种精细化学品工程实验室,广东广州510650 [2]国科广化韶关新材料研究院国科广化(南雄)新材料研究院有限公司,广东南雄512400 [3]中国科学院大学,北京100049

出　　处：《广州化学》2025年第1期1-8,I0001,共9页Guangzhou Chemistry

基　　金：国家自然科学基金(51173204、51503124、21404121、214041222);广州市科学技术项目(202102021194);清远科技项目(2022YFJH004)。

摘　　要：聚电解质因其优异的离子传输性能广泛应用于膜分离和储能电池领域。本文通过分子动力学模拟研究了聚丙烯酸盐(PAS)在不同溶剂体系(乙醇-水和电解液)及不同反离子作用下的构象和离子传输性能。通过分析自由体积、链回转半径(R_g)和二面角、径向分布函数(RDF)和均方位移(MSD)等参数,探究了Li^(+)、Na^(+)和Cs^(+)三种反离子对聚丙烯酸(PAA)分子链构象的调控作用及在其中离子迁移行为的影响。模拟结果表明,Li^(+)由于其较小的离子半径和较高的电荷密度,更倾向于引起链的收缩并形成更紧凑的构象。相较于Na^(+)和Cs^(+),Li^(+)在乙醇-水溶剂中表现出更高的吸附能(1.31 eV)和配位数,增强了其与PAA链的结合,促进了稳定离子传输通路的形成。在电解液体系中,Li^(+)表现出更高的离子迁移率(1.2×10^(-10)m^(2)/s)和扩散系数(4.7×10^(-9)m^(2)/(V·s)),尤其在外加电场作用下其传输性能显著优于其他同族离子。本研究从分子层面揭示了溶剂环境和反离子对聚电解质膜的构象与离子传导性能的影响机制,为离子选择性材料的设计与优化提供了理论支持。Polyelectrolyte are widely used in the field of membrane separation and energy storage batteries due to their excellent ion transport properties.In this paper,the conformational and ion-transport properties of poly(acrylate salt)(PAS)are investigated by molecular dynamics simulations in the presence of different solvent systems(ethanol-water and electrolyte)and counter-ions.By analyzing parameters such as free volume,chain radius of gyration(R_g)and dihedral angle,radial distribution function(RDF)and mean square displacement(MSD),the role of counter-ions in regulating the chain conformation of poly(acrylic acid)(PAA)molecules and their effects on ion migration behavior were investigated.The simulation results show that Li^(+)is more inclined to cause chain contraction and form a more compact conformation due to its smaller ionic radius and higher charge density.Compared to Na^(+)and Cs^(+),Li^(+)exhibited a higher adsorption energy(1.31 eV)and coordination number in ethanol-water solvent,which enhanced its binding to the PAA chain and facilitated the formation of a stabilized ion transport pathway.In the electrolyte solvent,Li^(+)exhibits higher diffusion coefficient(1.2×10^(-10)m^(2)/s)and ion mobility(4.7×10^(-9)m^(2)/(V·s)),and its transport properties are significantly better than other ions of the same group,especially under the effect of an external electric field.It reveals the mechanism of the influence of solvent environment and counter-ions on the conformational and ionic conductivity properties of polyelectrolyte membranes at the molecular level,which provides theoretical support for the design and optimization of ion-selective materials.

关 键 词：聚丙烯酸盐 乙醇-水 电解液 分子动力学模拟 离子传输 

分 类 号：O631.12[理学—高分子化学]