The spreading dynamics of the gravity-driven liquid motion on an inclined solid surface was studied by considering two fundamental physical models: the molecular kinetic theory and the hydrodynamic theory (HDT). The molecular kinetic theory is the most appropriate model to describe the gravity driven spreading mechanism investigated in this study. The gravity driven spreading which is one form of the forced spreading mechanism was compared with the spontaneous spreading for the same liquid/solid system from previous study by Mohammad Karim et al (2016 Langmuir 32 10153). Unlike the gravity driven spreading, the HDT was appropriate model to define the spontaneous spreading. This finding reveals the importance of the mechanism of spreading which are the forced and the spontaneous on the suitability of the physical model such as the molecular kinetic theory and the HDT to describe the spreading dynamics.

通过考虑两个基本物理模型：分子动力学理论和流体动力学理论 (HDT)，研究了倾斜固体表面上重力驱动的液体运动的扩散动力学。分子动力学理论是描述本研究中研究的重力驱动扩散机制的最合适的模型。在 Mohammad Karim等人(2016 Langmuir 32)之前的研究中，重力驱动的扩散是强制扩散机制的一种形式，与相同液体/固体系统的自发扩散进行了比较10153）。与重力驱动的扩散不同，HDT 是定义自发扩散的合适模型。这一发现揭示了扩散机制的重要性，即强制和自发的扩散机制对物理模型（如分子动力学理论和 HDT）描述扩散动力学的适用性的重要性。