Anomalous Phase Behaviors of Monolayer NaCl Aqueous Solutions Induced by Effective Coulombic Interactions within Angstrom-Scale Slits

作者：Zhao, Xiaorong; Liu, Yuying; Lin, Dongdong; Zhu, Weiduo; Ma, Nan; Xu, Wen Wu; Zhao, Wenhui^*; Sun, Yunxiang^*; Zeng, Xiao Cheng^*

来源：Journal of Physical Chemistry Letters, 2022, 13(12): 2704-2710.

DOI：10.1021/acs.jpclett.2c00501

• CONFINED WATER
• TRANSPORT
• ICE
• IONS
• TRANSITION
• MECHANISM

Interests in subnanofluidic devices have called for moleculardynamics (MD) simulation studies of the thermodynamic behavior of monolayersalt solution within angstrom-scale slits. However, it still remains a grand challengeto accurately describe the Coulombic interactions by incorporating the effects ofcharge transfer and electronic dielectric screening. Herein, by using the electroniccontinuum model, where the effective ion charges arefine-tuned with a scalingfactor of lambda, we present simulation evidence that the effective Coulombicinteractions among Na+/Cl-ions can strongly affect the behavior of monolayerionic aqueous solution. Our microsecond-scale MD simulations show that only thecounterions with moderate effective charges (0.3 <=lambda <= 0.8) can dissolve inmonolayer water, whereas the high effective charges (lambda >= 0.85) induce ions toassemble into monolayer nanocrystals, and ions with the low effective charges (lambda <= 0.2) exhibit gas-like nanobubble. Thesefindings could provide deeper insights intothe physical chemistry behind subnanofluidic iontronic devices