Lau A W C, Pincus P
Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19104, USA.
Phys Rev E Stat Nonlin Soft Matter Phys. 2002 Oct;66(4 Pt 1):041501. doi: 10.1103/PhysRevE.66.041501. Epub 2002 Oct 7.
We consider an overall neutral system consisting of two similarly charged plates and their oppositely charged counterions and analyze the electrostatic interaction between the two surfaces beyond the mean-field Poisson-Boltzmann approximation. Our physical picture is based on the fluctuation-driven counterion condensation model, in which a fraction of the counterions is allowed to "condense" onto the charged plates. In addition, an expression for the pressure is derived, which includes fluctuation contributions of the whole system. We find that for sufficiently high surface charges, the distance at which the attraction, arising from charge fluctuations, starts to dominate can be large compared to the Gouy-Chapmann length. We also demonstrate that depending on the valency, the system may exhibit a first-order binding transition at short distances.
我们考虑一个由两个带相似电荷的平板及其带相反电荷的抗衡离子组成的整体中性系统，并在平均场泊松-玻尔兹曼近似之外分析两个表面之间的静电相互作用。我们的物理图像基于涨落驱动的抗衡离子凝聚模型，其中一部分抗衡离子被允许“凝聚”到带电平板上。此外，还推导了一个压力表达式，其中包括整个系统的涨落贡献。我们发现，对于足够高的表面电荷，由电荷涨落引起的吸引力开始占主导的距离与古依-查普曼长度相比可能很大。我们还证明，根据价态的不同，该系统在短距离内可能会表现出一级结合转变。
