Directed percolation identified as equilibrium pre-transition towards non-equilibrium arrested gel states

作者：Kohl M; Capellmann R F; Laurati M; Egelhaaf S U; Schmiedeberg M

来源：Nature Communications, 2016, 7(1): 11817.

DOI：10.1038/ncomms11817

<jats:title>Abstract</jats:title><jats:p>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.</jats:p>

• 出版日期2016-6