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离子液体双层膜长寿命电场的实验证据
作者:小柯机器人 发布时间:2021/10/21 15:59:51

澳大利亚科廷大学Simone Ciampi团队报道了离子液体双层膜长寿命电场的实验证据。相关研究成果发表在2021年10月16日出版的《美国化学会杂志》。

该文中,研究人员证明了离子液体可以形成长寿命的双层,产生可通过直接开路电位(OCP)测量检测到的电场。在咪唑基离子液体中,外部负电压脉冲导致极为稳定的近表面偶极层,其场表现为OCP中的长寿命(~1–100 h)离散平台随时间的变化。该平台出现在离子液体特有的、尖锐的电位窗口内,研究人员定义了一种简单的实验方法来探测界面有序现象的开始,如过筛和拥挤。分子动力学模型显示,OCP产生于单个离子偶极子与外部电场脉冲的对齐,产生的OCP的大小与阳离子的投影偶极矩和阳离子扩散系数与其体积之比的乘积相关。

该研究结果还表明,如果界面首先通过拥挤,则更可能形成稳定的过筛结构,可能解释了离子液体中近表面结构弛豫动力学的分散文献数据。

附:英文原文

Title: Experimental Evidence of Long-Lived Electric Fields of Ionic Liquid Bilayers

Author: Mattia Belotti, Xin Lyu, Longkun Xu, Peter Halat, Nadim Darwish, Debbie S. Silvester, Ching Goh, Ekaterina I. Izgorodina, Michelle L. Coote, Simone Ciampi

Issue&Volume: October 16, 2021

Abstract: Herein we demonstrate that ionic liquids can form long-lived double layers, generating electric fields detectable by straightforward open circuit potential (OCP) measurements. In imidazolium-based ionic liquids an external negative voltage pulse leads to an exceedingly stable near-surface dipolar layer, whose field manifests as long-lived (~1–100 h) discrete plateaus in OCP versus time traces. These plateaus occur within an ionic liquid-specific and sharp potential window, defining a simple experimental method to probe the onset of interfacial ordering phenomena, such as overscreening and crowding. Molecular dynamics modeling reveals that the OCP arises from the alignment of the individual ion dipoles to the external electric field pulse, with the magnitude of the resulting OCP correlating with the product of the projected dipole moment of the cation and the ratio between  the cation diffusion coefficient  and its volume. Our findings also reveal that a stable overscreened structure is more likely to form if the interface is first forced through crowding, possibly accounting for the scattered literature data on relaxation kinetics of near-surface structures in ionic liquids.

DOI: 10.1021/jacs.1c06385

Source: https://pubs.acs.org/doi/10.1021/jacs.1c06385

 

期刊信息

JACS:《美国化学会志》,创刊于1879年。隶属于美国化学会,最新IF:14.612
官方网址:https://pubs.acs.org/journal/jacsat
投稿链接:https://acsparagonplus.acs.org/psweb/loginForm?code=1000