Fig. 1: System definition, coacervate formation, and ionic nature of the coacervates.

A Schematic representation of atomistic-to-coarse-grained (CG) mapping of PDDA monomer, ATP molecule implemented in this work. B A snapshot of PDDA-ATP coacervate with associated ions and water beads just before transferring it to DI water. Counterions and water molecules enclosed in the black curved boundary (a curved surface in 3D) are at a distance smaller than 1 nm to any PDDA or ATP beads. Counterions and water outside this surface are discarded while transferring. C Time evolution of the fraction of PDDA and ATP molecules in the largest cluster (f_cluster) in the supernatant (top) and DI water (bottom) for a selected simulation set. The same for all 8 sets are shown in Supplementary Figs. 18 and 19, respectively, for supernatant and DI water. We consider the cluster fully formed after f_cluster reaches a stable value of 1.0. The snapshots in the insets are the simulation box at indicated simulation times where PDDA, ATP, and small ions beads are colored red, blue, and green, respectively. D Projection of the clustered PDDA and ATP beads' (coacervates) positions on three principal planes of the cluster for a selected set. The same for all 8 sets is shown in Supplementary Fig. 20. This projection informs about the coacervate size and shape (e.g., asphericity). We also used these projections to label the “surface” and “core” of coacervates. The overlapping rectangular area is used to identify a core represented by a sphere with a radius of r_core = 2.8 nm. In between r_core = 2.8 nm and r_surface = 5 nm is considered as surface. Here, coordinate 1 and 2 are the pairs of principal axes orthogonal to the projected axis. Three colored regions are projections of PDDA and ATP beads on three principal planes. E Time evolution of the number of Na⁺ and Cl⁻ ions within the coacervate in “supernatant” after the coacervate forms (i) and “DI water” (ii) for a selected set. Time evolution of the ratio of the number of Na⁺ to Cl⁻ ions within the coacervate in “supernatant” (iii) and “DI water” (iv) for a selected set. The same for all 8 sets are shown in Supplementary Figs. 1 and 2, respectively, for supernatant and DI water. Yellow lines in the lower panel indicate a running average (which is higher than 1) both in supernatant and DI water.