Ramírez-Kantun Roger, Pérez-Ángel Gabriel, Castañeda-Priego Ramón
Departamento de Física Aplicada, CINVESTAV Mérida, Km. 6 Antigua carretera a Progreso, Cordemex, 97310 Mérida, Mexico.
Departamento de Ingeniería Física, Universidad de Guanajuato, Loma del Bosque 103, 37150 León, Mexico.
J Chem Phys. 2024 Feb 14;160(6). doi: 10.1063/5.0187840.
During the last few years, patchy colloidal dispersions have emerged as ideal candidates of glass-formers of systems composed of particles that interact with non-isotropic potentials. However, from the computational point of view, the characterization of their dynamical properties close to the glass transition via any kind of molecular dynamics simulation technique can be very difficult due to the slowing down of both the rotational and translational dynamics. Although a plethora of dynamical techniques have been developed to account for the dynamics of patchy colloids, new and complementary simulation techniques are required to explore, much faster and more efficiently, the dynamical arrest transition of patchy colloidal dispersions when computer simulation consists of a large number of particles and, due to the slow particle dynamics at the glass transition, an extended time window is explicitly required. Then, in this contribution, by means of the so-called dynamic-Monte Carlo method, we report on the dynamical arrest transition, both rotational and translational, of a bidisperse patchy colloidal dispersion, following three different paths along the density-temperature plane, including high densities and low temperatures. Although this method has not been extensively tested at extreme thermodynamic conditions, we show that even at the dynamical arrest transition, it allows us to extract good dynamical data from a complex system. Therefore, it turns out to be a promising technique to explore the onset of vitrification of anisotropic colloidal particles.
在过去几年中，斑片状胶体分散体系已成为由与非各向同性势相互作用的粒子组成的系统中玻璃态形成体的理想候选者。然而，从计算的角度来看，由于旋转和平移动力学的减慢，通过任何一种分子动力学模拟技术来表征它们接近玻璃化转变时的动力学性质都可能非常困难。尽管已经开发了大量动力学技术来解释斑片状胶体的动力学，但当计算机模拟包含大量粒子时，由于玻璃化转变时粒子动力学缓慢，需要明确一个扩展的时间窗口，因此需要新的互补模拟技术来更快、更有效地探索斑片状胶体分散体系的动力学阻滞转变。然后，在本论文中，我们借助所谓的动态蒙特卡罗方法，沿着密度 - 温度平面上的三条不同路径，包括高密度和低温，报道了双分散斑片状胶体分散体系的旋转和平移动力学阻滞转变。尽管该方法在极端热力学条件下尚未得到广泛测试，但我们表明，即使在动力学阻滞转变时，它也能让我们从复杂系统中提取良好的动力学数据。因此，它成为探索各向异性胶体粒子玻璃化转变起始的一种有前途的技术。
