Gelation in physically associating polymer solutions

Simulations were performed on solutions of associating polymers, where the pairing energy between "stickers" is comparable to thermal energy, to gain insights into the nature of reversible gelation. At high temperatures, interchain associations relax over microscopic time scales, so that geometrical percolation is unrelated to macroscopic gelation. However, with decreasing temperature, the stickers undergo a clustering "transition," resulting in a transient localization of stickers and hence the chains. These findings imply a close similarity between the dynamics of associating polymer solutions and vitrification of glass-forming liquids, in agreement with many experimental results.