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Surface polarization effects in confined polyelectrolyte solutions.
Proceedings of the National Academy of Sciences of the United States of America ( IF 11.1 ) Pub Date : 2020-08-18 , DOI: 10.1073/pnas.2007545117
Debarshee Bagchi 1 , Trung Dac Nguyen 2 , Monica Olvera de la Cruz 2, 3, 4
Affiliation  

Understanding nanoscale interactions at the interface between two media with different dielectric constants is crucial for controlling many environmental and biological processes, and for improving the efficiency of energy storage devices. In this contributed paper, we show that polarization effects due to such dielectric mismatch remarkably influence the double-layer structure of a polyelectrolyte solution confined between two charged surfaces. Surprisingly, the electrostatic potential across the adsorbed polyelectrolyte double layer at the confining surface is found to decrease with increasing surface charge density, indicative of a negative differential capacitance. Furthermore, in the presence of polarization effects, the electrostatic energy stored in the double-layer structure is enhanced with an increase in the charge amplification, which is the absorption of ions on a like-charged surface. We also find that all of the important double-layer properties, such as charge amplification, energy storage, and differential capacitance, strongly depend on the polyelectrolyte backbone flexibility and the solvent quality. These interesting behaviors are attributed to the interplay between the conformational entropy of the confined polyelectrolytes, the Coulombic interaction between the charged species, and the repulsion from the surfaces with lower dielectric constant.



中文翻译:

受限聚电解质溶液中的表面极化效应。

了解介电常数不同的两种介质之间的界面处的纳米级相互作用对于控制许多环境和生物过程以及提高储能装置的效率至关重要。在这篇有贡献的论文中,我们表明,由于这种介电失配而引起的极化效应显着影响了限制在两个带电表面之间的聚电解质溶液的双层结构。出人意料的是,发现限制表面上跨吸附的聚电解质双层的静电势随着表面电荷密度的增加而降低,这表明负差分电容。此外,在存在极化效应的情况下,双层结构中存储的静电能随着电荷放大率的增加而增强,这是在带相同电荷的表面上吸收离子的过程。我们还发现,所有重要的双层特性(例如电荷放大,能量存储和差分电容)都强烈取决于聚电解质主链的柔韧性和溶剂质量。这些有趣的行为归因于受限的聚电解质的构象熵,带电物质之间的库仑相互作用以及来自介电常数较低的表面的排斥之间的相互作用。

更新日期:2020-08-19
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