Mokshin Anatolii V, Galimzyanov Bulat N, Barrat Jean-Louis
Kazan Federal University, 420000 Kazan, Russia.
Phys Rev E Stat Nonlin Soft Matter Phys. 2013 Jun;87(6):062307. doi: 10.1103/PhysRevE.87.062307. Epub 2013 Jun 14.
Nucleation is an out-of-equilibrium process that can be strongly affected by the presence of external fields. In this paper, we report a simple extension of classical nucleation theory to systems submitted to an homogeneous shear flow. The theory involves accounting for the anisotropy of the critical nucleus formation and introduces a shear-rate-dependent effective temperature. This extended theory is used to analyze the results of extensive molecular dynamics simulations that explore a broad range of shear rates and undercoolings. At fixed temperature, a maximum in the nucleation rate is observed, when the relaxation time of the system is comparable to the inverse shear rate. In contrast to previous studies, our approach does not require a modification of the thermodynamic description, as the effect of shear is mainly embodied into a modification of the kinetic prefactor and of the temperature.
成核是一个非平衡过程，会受到外部场的强烈影响。在本文中，我们报告了经典成核理论的一种简单扩展，用于适用于均匀剪切流的系统。该理论涉及考虑临界核形成的各向异性，并引入了一个与剪切速率相关的有效温度。这个扩展理论被用于分析大量分子动力学模拟的结果，这些模拟探索了广泛的剪切速率和过冷度范围。在固定温度下，当系统的弛豫时间与剪切速率的倒数可比时，观察到成核速率出现最大值。与之前的研究不同，我们的方法不需要修改热力学描述，因为剪切的影响主要体现在动力学前置因子和温度的修改上。
