Directed percolation identified as equilibrium pre-transition towards non-equilibrium arrested gel states.
Directed percolation identified as equilibrium pre-transition towards non-equilibrium arrested gel states.
复制标题
DOI：
10.1038/ncomms11817
复制
发表时间：
2016-06-09
影响因子：
16.6
通讯作者：
Schmiedeberg M
中科院分区：
文献类型：
--
作者：
Kohl M;Capellmann RF;Laurati M;Egelhaaf SU;Schmiedeberg M
凝胶的宏观性质源于其缓慢的动力学和承载网络结构，这被自然界和许多工业产品所利用。然而，这些结构和动力学性质之间的联系仍然难以捉摸。在这里，我们提出了共聚焦显微镜实验和模拟凝胶形成的胶体聚合物混合物。他们揭示了凝胶形成之前的连续和定向渗滤。这两种转变都导致系统跨越网络，但只有定向渗滤导致极慢的动力学，老化和类似于脱水收缩的凝胶收缩。因此，动态逮捕凝胶被发现是链接到一个结构转变，即定向渗滤，这是定量与平均数的键合邻居。定向渗流表示一个普适的过渡类。因此，我们的研究将凝胶形成与一个成熟的理论框架联系起来，现在可以利用这个理论框架来详细了解被捕凝胶。 凝胶表现出非常缓慢的动力学，其结构原因仍然难以捉摸。在这里，Kohl等人表明，凝胶形成伴随着连续和定向的渗滤，只有后者发现导致被捕动态。
The macroscopic properties of gels arise from their slow dynamics and load-bearing network structure, which are exploited by nature and in numerous industrial products. However, a link between these structural and dynamical properties has remained elusive. Here we present confocal microscopy experiments and simulations of gel-forming colloid–polymer mixtures. They reveal that gel formation is preceded by continuous and directed percolation. Both transitions lead to system-spanning networks, but only directed percolation results in extremely slow dynamics, ageing and a shrinking of the gel that resembles synaeresis. Therefore, dynamical arrest in gels is found to be linked to a structural transition, namely directed percolation, which is quantitatively associated with the mean number of bonded neighbours. Directed percolation denotes a universality class of transitions. Our study hence connects gel formation to a well-developed theoretical framework, which now can be exploited to achieve a detailed understanding of arrested gels. Gels exhibit very slow dynamics, for which a structural reason remains elusive. Here, Kohl et al. show the gel formation is accompanied by a succession of continuous and directed percolation, with only the latter found to lead to the arrested dynamics.