It has been a long-lasting debate on the position of zeta potential plane within aqueous solutions. This paper reports a flexible behavior of the inactive electrokinetic layer between the outer-Helmholtz plane and zeta potential plane, so-called buffer layer, in response to bulk ion concentration. This flexibility is not only corroborated by analyzing the measured zeta potentials with resulting electrical quad-layer model (inner- and outer-Helmholtz, buffer, and diffuse layers) but also consistent with thermodynamic analysis. The model indicates that the flexible buffer layer thickness saturates to its minimum for concentrated solutions. The predicted ionic conductance agrees well with the previous experimental measurements in nanochannels. The theory provides a deep physical insight into understanding, design, and manipulation of ion transport in nanosystems.

关于zeta电位平面在水溶液中的位置一直存在着长期的争论。本文报道了外部亥姆霍兹平面和zeta电位平面之间的非活动电动层（称为缓冲层）响应体离子浓度的灵活行为。这种灵活性不仅可以通过使用生成的电四层模型（内亥姆霍兹层和外亥姆霍兹层，缓冲层和扩散层）分析测得的zeta电位得到证实，而且还与热力学分析一致。该模型表明，对于浓缩溶液，柔性缓冲层的厚度会饱和到其最小值。预测的离子电导率与先前在纳米通道中进行的实验测量非常吻合。该理论为理解，设计，