Hutchens Shelby B, Wang Zhen-Gang
Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA.
J Chem Phys. 2007 Aug 28;127(8):084912. doi: 10.1063/1.2761891.
The authors examine the possibility of a two-step nucleation to the bulk condensation transition that proceeds via a metastable liquid cluster intermediate having some preferred size. The metastable intermediate is stabilized by electrostatic repulsion, which becomes screened by small mobile ions at sufficiently large cluster sizes, thus allowing the eventual condensation to a bulk phase. Our calculation employs a capillary model for the cluster and the electrostatic interactions are treated using the Poisson-Boltzmann approach. Condensation via this metastable intermediate may be a very general phenomenon which applies not only to solutions of charged particles (e.g., proteins, colloidal particles, and polyelectrolytes) but to any system involving short-range attraction and long-range repulsion undergoing macrophase separation in which a metastable microphase separation is also possible.
作者研究了两步成核至体相凝聚转变的可能性，该转变通过具有某种优选尺寸的亚稳液体团簇中间体进行。亚稳中间体通过静电排斥得以稳定，在足够大的团簇尺寸下，小的移动离子会屏蔽这种静电排斥，从而使得最终凝聚为体相。我们的计算采用了针对团簇的毛细管模型，并使用泊松 - 玻尔兹曼方法处理静电相互作用。经由这种亚稳中间体的凝聚可能是一种非常普遍的现象，它不仅适用于带电粒子（例如蛋白质、胶体粒子和聚电解质）的溶液，还适用于任何涉及短程吸引和长程排斥且经历宏观相分离的系统，在这种系统中也可能发生亚稳微相分离。
