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为了解释有关纳米通道内离子输运特性的一系列违反经典流体力学和电迁移理论的实验现象的内在机理,通过分子动力学模拟的方法,研究了受限高浓度Na Cl溶液的离子电流和迁移率等电动力学输运特性.结果显示,跨膜电压和接入电阻是导致单层石墨烯纳米孔的离子电流随孔径呈线性增长的重要原因.受限电解质溶液与体态溶液的本质区别是除了固液界面的边界效应外,跨膜电压造成的局部超大电场将导致电迁移速率随电场强度增加出现非线性增长的Wien效应.同时,离子迁移率随溶液浓度升高而下降.产生这些变化的微观机理除了离子氛屏蔽效应外,还有离子对形成和离子碰撞等离子间微观相互作用.
In order to explain the intrinsic mechanism of a series of experimental phenomena in violation of the classical hydrodynamics and electromigration theory concerning the ion transport characteristics in nanochannels, the ion current and migration of the highly concentrated NaCl solution were studied by molecular dynamics simulation Rate and other electrokinetic transport properties.The results show that the transmembrane voltage and the access resistance is the main reason leading to the linear increase of the ion current with the pore size of the single graphene nanopore.The essential difference between the limited electrolyte solution and the body solution is In addition to the boundary effect of the solid-liquid interface, the local super-electric field caused by the transmembrane voltage will lead to the Wien effect of nonlinear increase of the electromigration rate with the increase of the electric field intensity. Meanwhile, the ion mobility decreases with the increase of the solution concentration In addition to the micro-mechanism of ion shielding effect, there are ion-pair formation and ion-collision plasma microscopic interaction.