Departamento de Física, Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa, Portugal.
Centro de Física Teórica e Computacional, Universidade de Lisboa, 1749-016 Lisboa, Portugal and Instituto Superior de Engenharia de Lisboa, ISEL, Avenida Conselheiro Emídio Navarro, 1 1950-062 Lisboa, Portugal.
Soft Matter. 2018 Apr 4;14(14):2744-2750. doi: 10.1039/C7SM01996C.
Low-density networks of molecules or colloids are formed at low temperatures when the interparticle interactions are valence limited. Prototypical examples are networks of patchy particles, where the limited valence results from highly directional pairwise interactions. We combine extensive Langevin simulations and Wertheim's theory of association to study these networks. We find a scale-free (relaxation) dynamics within the liquid-gas coexistence region, which differs from that usually observed for isotropic particles. While for isotropic particles the relaxation dynamics is driven by surface tension (coarsening), when the valence is limited, the slow relaxation proceeds through the formation of an intermediate non-equilibrium gel via a geometrical percolation transition in the Random Percolation universality class. We show that the slow dynamics is universal, being also observed outside the coexistence region at low temperatures in the single phase region.
在低温下，当粒子间相互作用受配位数限制时，会形成低浓度的分子或胶体网络。典型的例子是带有补丁的粒子网络，其中受限制的配位数是由高度定向的两两相互作用导致的。我们结合了广泛的朗之万模拟和 Wertheim 的缔合理论来研究这些网络。我们发现在液体-气体共存区域内存在无标度（弛豫）动力学，这与通常观察到的各向同性粒子的动力学不同。对于各向同性粒子，弛豫动力学是由表面张力（粗化）驱动的，而当配位数受到限制时，缓慢的弛豫则通过在随机渗流普适类中形成中间非平衡凝胶来进行，这是一种几何渗流转变。我们表明，这种缓慢的动力学是普遍存在的，即使在低温单相区共存区之外也能观察到。
