División de Ciencias e Ingenierías, Campus León, Universidad de Guanajuato, Loma del Bosque 103, 37150 León, Guanajuato, Mexico.
Department of Chemical and Biological Engineering, Illinois Institute of Technology, 3440 S. Dearborn Street, Chicago, Illinois 60616, USA.
Phys Rev Lett. 2018 Jun 15;120(24):248004. doi: 10.1103/PhysRevLett.120.248004.
Cluster morphology of spherical particles interacting with a short-range attraction has been extensively studied due to its relevance to many applications, such as the large-scale structure in amorphous materials, phase separation, protein aggregation, and organelle formation in cells. Although it was widely accepted that the range of the attraction solely controls the fractal dimension of clusters, recent experimental results challenged this concept by also showing the importance of the strength of attraction. Using Monte Carlo simulations, we conclusively demonstrate that it is possible to reduce the dependence of the cluster morphology to a single variable, namely, the reduced second virial coefficient, B_{2}^{}, linking the local properties of colloidal systems to the extended law of corresponding states. Furthermore, the cluster size distribution exhibits two well-defined regimes: one identified for small clusters, whose fractal dimension, d_{f}, does not depend on the details of the attraction, i.e., small clusters have the same d_{f}, and another related to large clusters, whose morphology depends exclusively on B_{2}^{}, i.e., d_{f} of large aggregates follows a master curve, which is only a function of B_{2}^{*}. This physical scenario is confirmed with the reanalysis of experimental results on colloidal-polymer mixtures.
由于与许多应用相关，如无定形材料的大结构、相分离、蛋白质聚集和细胞细胞器形成，球形颗粒与短程吸引力相互作用的团簇形态已经得到了广泛的研究。尽管人们普遍认为吸引力的范围仅控制团簇的分形维数，但最近的实验结果表明吸引力的强度也很重要，这对这一概念提出了挑战。通过使用蒙特卡罗模拟，我们明确证明，可以将团簇形态的依赖性归结为一个单一变量，即，降低第二维里系数 B_{2}^{}，将胶体系统的局部性质与扩展的对应状态定律联系起来。此外，团簇大小分布表现出两个明显的区域：一个与小团簇相关，其分形维数 d_{f}不依赖于吸引力的细节，即小团簇具有相同的 d_{f}，另一个与大团簇相关，其形态仅取决于 B_{2}^{}，即大聚集体的 d_{f}遵循主曲线，该曲线仅为 B_{2}^{*}的函数。这一物理情景得到了对胶体-聚合物混合物的实验结果的重新分析的证实。
