Zwitterions Raise the Dielectric Constant of Soft Materials
Zwitterions Raise the Dielectric Constant of Soft Materials
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DOI：
10.1103/physrevlett.127.228001
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发表时间：
2021-11-24
影响因子：
8.6
通讯作者：
Colby, Ralph H.
中科院分区：
文献类型：
--
作者：
Mei, Wenwen;Rothenberger, August J.;Colby, Ralph H.
表现出高介电常数（ε）的材料对于能量存储和致动器是关键的。增加分散度的成功方法是掺入极性添加剂（具有高分散度），但难以控制所得分散状态。在这里，我们表明，显着的增加是通过添加两性离子，这是一个阳离子和一个阴离子的共价键分离的小分子实现的。随着两性离子的加入，Δ（s）的增加归因于两性离子的大分子偶极，范围从35到41 D，如实验量化的和使用密度泛函理论证实的。在乙二醇介质中两性离子浓度升高时，由于两性离子之间的强库仑相互作用，两性离子的非线性增加最终饱和。所提出的工作提供了一个基本的分子理解，为什么两性离子是有效的添加剂，提高es在软材料。
Materials exhibiting high dielectric constants (epsilon(s)) are critical for energy storage and actuators. A successful approach to increase epsilon(s) is to incorporate polar additives (with high epsilon(s)) but controlling the resulting dispersion state is difficult. Here, we show that significant epsilon(s) increases are realized by adding zwitterions, which are small molecules with a cation and an anion separated by covalent bonds. The increase in epsilon(s) with zwitterion addition is attributed to the large molecular dipole of zwitterions, ranging from 35 to 41 D, as experimentally quantified and confirmed using density functional theory. At elevated zwitterion concentration in an ethylene glycol medium, there is a nonlinear increase of epsilon(s) that eventually saturates due to the strong Coulombic interactions between zwitterions. The presented work provides a fundamental molecular understanding of why zwitterions are effective additives in boosting es in soft materials.