Chemical reaction motifs driving non-equilibrium behaviors in phase separating materials

Abstract: Chemical reactions that couple to systems that phase separate have been implicated in diverse contexts from biology to materials science. However, how a particular set of chemical reactions (chemical reaction network, CRN) would affect the behaviors of a phase separating system is difficult to fully predict theoretically. In this paper, we analyze a mean field theory coupling CRNs to phase separating materials and expound on how the properties of the CRNs affect different classes of non-equilibrium behaviors: the emergence of microphase separation or of temporally oscillating patterns. We examine the problem of achieving microphase separated condensates by first considering tractable problems and illustrating the mathematical conditions leading to microphase separation. We then identify CRN motifs that are likely to yield size control by examining randomly generated networks and parameters. By analyzing the probabilities to observe particular states, we define simple design rules of CRNs that lead to desired non-equilibrium behavior. We show that chemical interactions generating negative feedback facilitate microphase separation, moreover, we demonstrate that the parameters important for the emergence of microphase separation differ for systems with two or four components, due to frustration. Our results provide guidance toward the design of self-regulating material CRNs and provide instructions to manage the formation, dissolution, and organization of compartments.