Effect of network topology on phase separation in two-dimensional Lennard-Jones networks.

We generate two-dimensional Lennard-Jones networks with random topology by preparing a perfect four-functional network of identical harmonic springs and randomly cutting some of the springs. Using molecular-dynamics simulations we find that the fraction p of active springs affects both the temperature of phase separation and the type of structures observed below this temperature, from networklike high-density patterns at p>0.5 ("gel") to dropletlike structures at p<0.5 ("sol"). In the gel domain, these patterns are determined by the interplay between free energy and network topology, with the former dominant as p-->1 and the latter as p-->0.5 .