论文标题
多价电解质中双极纳米孔的纠正：电荷反转和强离子相关的影响
Rectification of bipolar nanopores in multivalent electrolytes: effect of charge inversion and strong ionic correlations
论文作者
论文摘要
由于纳米孔壁上的电荷模式的不对称性，双极纳米孔具有强大的整流性能。特别是，双极纳米孔沿着孔轴具有正面和负表面电荷。如果与电解质的筛选长度相比，纳米孔的半径很小，因此阳离子和阴离子在各个区域都有耗尽的区域，则矫正是强的。这些耗尽区的深度对外部电压的迹象很敏感。在这项工作中，由于存在多价离子和较大的表面电荷，我们对存在强离子相关性的影响（离子和离子和表面电荷之间）感兴趣。我们表明，强的离子相关性会导致COIONS的泄漏，这是平均野外理论中不存在的现象。 In this modeling study, we use both the mean-field Poisson-Nernst-Planck (PNP) theory and a particle simulation method, Local Equilibrium Monte Carlo (LEMC), to show that phenomena such as overcharging and charge inversion cannot be reproduced with PNP, while LEMC is able to produce nonmonotonic dependence of currents and rectification as a function of surface charge strength.
Bipolar nanopores have powerful rectification properties due to the asymmetry in the charge pattern on the wall of the nanopore. In particular, bipolar nanopores have positive and negative surface charges along the pore axis. Rectification is strong if the radius of the nanopore is small compared to the screening length of the electrolyte so that both cations and anions have depletion zones in the respective regions. The depths of these depletion zones is sensitive to sign of the external voltage. In this work, we are interested in the effect of the presence of strong ionic correlations (both between ions and between ions and surface charge) due to the presence of multivalent ions and large surface charges. We show that strong ionic correlations cause leakage of the coions, a phenomenon that is absent in mean field theories. In this modeling study, we use both the mean-field Poisson-Nernst-Planck (PNP) theory and a particle simulation method, Local Equilibrium Monte Carlo (LEMC), to show that phenomena such as overcharging and charge inversion cannot be reproduced with PNP, while LEMC is able to produce nonmonotonic dependence of currents and rectification as a function of surface charge strength.
