Department of Mechanical Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.
J Chem Phys. 2023 Apr 7;158(13):134717. doi: 10.1063/5.0140878.
The present investigation assesses a variety of parameters available in the literature to model gold-water interfaces using molecular dynamics simulations. The study elucidates the challenges of characterizing the solid-liquid affinity of highly hydrophilic gold-water interfaces via wettability. As an alternative, the local pairwise interaction energy was used to describe the solid-liquid affinity of flat and curved surfaces, where for the latter, the calculation of a contact angle becomes virtually impossible. Regarding the heat transfer properties of different interface models (flat and curved), partly conclusive trends were observed between the total pairwise interaction energy and the thermal boundary conductance. It was observed that the solid surface structure, interfacial force field type, and force field parameters created a characteristic bias in the interfacial water molecules (liquid structuring). Consequently, a study of the liquid depletion layer provided better insight into the interfacial heat transfer among different interfaces. By computing the density depletion length, which describes the deficit or surplus of energy carries (water molecules) near the interface, a proper characterization of the thermal boundary conductance was obtained for the different gold-water interfaces. It was observed that the interfacial heat transfer is favored when the water molecules organize in cluster-like structures near the interface, by a surplus of water molecules at the interface, i.e., lower density depletion length, and by the closeness of water to the solid atoms.
本研究评估了文献中可用的各种参数，以使用分子动力学模拟来模拟金-水界面。该研究阐明了通过润湿性来表征高亲水性金-水界面固-液亲和力的挑战。作为替代方案，使用局部成对相互作用能来描述平面和曲面的固-液亲和力，对于后者，计算接触角实际上是不可能的。关于不同界面模型（平面和曲面）的传热性质，在总成对相互作用能和热边界传导率之间观察到部分结论性趋势。观察到的是，固体表面结构、界面力场类型和力场参数在界面水分子（液体结构）中产生了特征偏差。因此，对液体耗尽层的研究提供了对不同界面之间界面传热的更好了解。通过计算密度耗尽长度，该长度描述了界面附近能量载体（水分子）的不足或过剩，从而可以对不同的金-水界面获得适当的热边界传导率描述。观察到的是，当水分子在界面附近以类簇结构组织时，界面传热会得到促进，即界面处水分子过剩，即密度耗尽长度较低，以及水分子接近固体原子。
