Scalfi Laura, Rotenberg Benjamin
Physicochimie des Électrolytes et Nanosystèmes Interfaciaux, Sorbonne Université, CNRS, F-75005 Paris, France.
Physicochimie des Électrolytes et Nanosystèmes Interfaciaux, Sorbonne Université, CNRS, F-75005 Paris, France;
Proc Natl Acad Sci U S A. 2021 Dec 14;118(50). doi: 10.1073/pnas.2108769118.
We investigate the effect of the metallic character of solid substrates on solid-liquid interfacial thermodynamics using molecular simulations. Building on the recent development of a semiclassical Thomas-Fermi model to tune the metallicity in classical molecular dynamics simulations, we introduce a thermodynamic integration framework to compute the evolution of the interfacial free energy as a function of the Thomas-Fermi screening length. We validate this approach against analytical results for empty capacitors and by comparing the predictions in the presence of an electrolyte with values determined from the contact angle of droplets on the surface. The general expression derived in this work highlights the role of the charge distribution within the metal. We further propose a simple model to interpret the evolution of the interfacial free energy with voltage and Thomas-Fermi length, which allows us to identify the charge correlations within the metal as the microscopic origin of the evolution of the interfacial free energy with the metallic character of the substrate. This methodology opens the door to the molecular-scale study of the effect of the metallic character of the substrate on confinement-induced transitions in ionic systems, as reported in recent atomic force microscopy and surface force apparatus experiments.
我们使用分子模拟研究了固体基底的金属特性对固液界面热力学的影响。基于最近在经典分子动力学模拟中用于调节金属性的半经典托马斯 - 费米模型的发展，我们引入了一个热力学积分框架来计算界面自由能随托马斯 - 费米屏蔽长度的演化。我们通过与空电容器的解析结果进行对比，并将存在电解质时的预测结果与由液滴在表面的接触角确定的值进行比较，来验证这种方法。这项工作中推导的一般表达式突出了金属内部电荷分布的作用。我们进一步提出了一个简单模型来解释界面自由能随电压和托马斯 - 费米长度的演化，这使我们能够将金属内部的电荷相关性确定为界面自由能随基底金属特性演化的微观起源。正如最近在原子力显微镜和表面力装置实验中所报道的那样，这种方法为在分子尺度上研究基底金属特性对离子系统中受限诱导转变的影响打开了大门。
