Aasen Ailo, Reguera David, Wilhelmsen Øivind
Department of Energy and Process Engineering, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway.
SINTEF Energy Research, NO-7465 Trondheim, Norway.
Phys Rev Lett. 2020 Jan 31;124(4):045701. doi: 10.1103/PhysRevLett.124.045701.
The study of nucleation in fluid mixtures exposes challenges beyond those of pure systems. A striking example is homogeneous condensation in highly surface-active water-alcohol mixtures, where classical nucleation theory yields an unphysical, negative number of water molecules in the critical embryo. This flaw has rendered multicomponent nucleation theory useless for many industrial and scientific applications. Here, we show that this inconsistency is removed by properly incorporating the curvature dependence of the surface tension of the mixture into classical nucleation theory for multicomponent systems. The Gibbs adsorption equation is used to explain the origin of the inconsistency by linking the molecules adsorbed at the interface to the curvature corrections of the surface tension. The Tolman length and rigidity constant are determined for several water-alcohol mixtures and used to show that the corrected theory is free of physical inconsistencies and provides accurate predictions of the nucleation rates. In particular, for the ethanol-water and propanol-water mixtures, the average error in the predicted nucleation rates is reduced from 11-15 orders of magnitude to below 1.5. The curvature-corrected nucleation theory opens the door to reliable predictions of nucleation rates in multicomponent systems, which are crucial for applications ranging from atmospheric science to research on volcanos.
对流体混合物中成核现象的研究面临着比纯系统更多的挑战。一个显著的例子是在高表面活性的水 - 醇混合物中的均匀凝结，在这种情况下，经典成核理论得出临界胚胎中水分子数量为非物理的负数。这一缺陷使得多组分成核理论在许多工业和科学应用中毫无用处。在此，我们表明，通过将混合物表面张力的曲率依赖性恰当地纳入多组分系统的经典成核理论中，可以消除这种不一致性。吉布斯吸附方程通过将吸附在界面的分子与表面张力的曲率修正联系起来，解释了这种不一致性的起源。确定了几种水 - 醇混合物的托尔曼长度和刚性常数，并用于表明修正后的理论不存在物理上的不一致性，并且能够准确预测成核速率。特别是，对于乙醇 - 水和丙醇 - 水混合物，预测成核速率的平均误差从11 - 15个数量级降低到1.5以下。曲率修正的成核理论为可靠预测多组分系统中的成核速率打开了大门，这对于从大气科学到火山研究等各种应用至关重要。
