Generalized models for bond percolation transitions of associative polymers

Abstract: Associative polymers with sticker-and-spacer architectures undergo phase transitions that combine phase separation and bond percolation. Here, we generalize mean-field models for bond percolation and extract effective sticker interaction strengths from experimental data for specific proteins. We use graph-based Monte Carlo simulations to evaluate effects ignored by mean-field models. These include bond cooperativity defined as changes to strengths of new bonds (physical crosslinks) given the presence of a prior bond. We find that bond cooperativity fundamentally alters phase behavior, especially in sub-stoichiometric regimes for valencies of complementary stickers.