DPD simulations were performed using the dl meso simulation package and we adopt a DPD time step of 0.01 DPD time units. Hereafter we shall, for the most part, express elapsed times in DPD time units. A constant pressure ensemble (NPT), following the Langevin piston implementation by Jakobsen was used, and we set the system pressure to P = 23.7 (DPD units) to match the pressure of pure water in the model defined by Groot . The electrostatics of the charged DPD beads were defined by the model of González-Melchor et al. which assumes a uniform dielectric constant (chosen to be equivalent to that of pure water by setting the electrostatic coupling parameter Γ = 15.4) in the simulation box. The electrostatics were solved using a smoothed-particle mesh Ewald (SPME) algorithm. All simulations were started from randomly dispersed initial configurations.