Computational Investigation of Sequence-Controlled Complex Coacervation in Statistical Copolymers

Control of the monomer sequence of polymeric materials provides a pathway for the design of materials that mimic biomacromolecular complexity. In practice, this control can be achieved by tuning the reaction kinetics of random polymerization of different monomers, where the primary sequence distribution follows a first-order Markov chain. In this work, classical Gibbs ensemble and molecular dynamics simulations are used to explore the phase diagrams of polyelectrolyte coacervates with distinct monomer sequences controlled by a simple model for statistical copolymerization. Our results are summarized in phase diagrams that are in line with our previous theoretical findings and experimental observations including the fact that high charge “blockiness” within the sequence results in denser coacervates. Simulations also explore the important role of salt ion specificity as manifested by excluded volume interactions, and how these effects influence complex coacervate thermodynamics. The results presented in this work provide a deeper understanding of how chemical sequence can be used to control complex coacervation.