Zhao Xiaorong, Liu Yuying, Lin Dongdong, Zhu Weiduo, Ma Nan, Xu Wen Wu, Zhao Wenhui, Sun Yunxiang, Zeng Xiao Cheng
Department of Physics, Ningbo University, Ningbo, Zhejiang 315211, China.
Department of Physics, Hefei University of Technology, Hefei, Anhui 230009, China.
J Phys Chem Lett. 2022 Mar 31;13(12):2704-2710. doi: 10.1021/acs.jpclett.2c00501. Epub 2022 Mar 18.
Interests in subnanofluidic devices have called for molecular dynamics (MD) simulation studies of the thermodynamic behavior of monolayer salt solution within angstrom-scale slits. However, it still remains a grand challenge to accurately describe the Coulombic interactions by incorporating the effects of charge transfer and electronic dielectric screening. Herein, by using the electronic continuum model, where the effective ion charges are fine-tuned with a scaling factor of λ, we present simulation evidence that the effective Coulombic interactions among Na/Cl ions can strongly affect the behavior of monolayer ionic aqueous solution. Our microsecond-scale MD simulations show that only the counterions with moderate effective charges (0.3 ≤ λ ≤ 0.8) can dissolve in monolayer water, whereas the high effective charges (λ ≥ 0.85) induce ions to assemble into monolayer nanocrystals, and ions with the low effective charges (λ ≤ 0.2) exhibit gas-like nanobubble. These findings could provide deeper insights into the physical chemistry behind subnanofluidic iontronic devices.
对亚纳米流体装置的兴趣促使人们对埃尺度狭缝内单层盐溶液的热力学行为进行分子动力学（MD）模拟研究。然而，通过纳入电荷转移和电子介电屏蔽效应来准确描述库仑相互作用仍然是一个巨大的挑战。在此，通过使用电子连续介质模型，其中有效离子电荷通过缩放因子λ进行微调，我们提供了模拟证据，表明Na/Cl离子之间的有效库仑相互作用会强烈影响单层离子水溶液的行为。我们的微秒级MD模拟表明，只有具有中等有效电荷（0.3≤λ≤0.8）的抗衡离子才能溶解在单层水中，而高有效电荷（λ≥0.85）会诱导离子组装成单层纳米晶体，低有效电荷（λ≤0.2）的离子则呈现气态纳米气泡。这些发现可以为亚纳米流体离子电子器件背后的物理化学提供更深入的见解。
