The structure and interaction mechanism of a polyelectrolyte complex: a dissipative particle dynamics study

Abstract

The mechanism of complex formation of two oppositely charged linear polyelectrolytes dispersed in a solvent is investigated by using dissipative particle dynamics (DPD) simulation. In the polyelectrolyte solution, the size of the cationic polyelectrolyte remains constant while the size of the anionic chain increases. We analyze the influence of the anionic polyelectrolyte size and salt effect (ionic strength) on the conformational changes of the chains during complex formation. The behavior of the radial distribution function, the end-to-end distance and the radius of gyration of each polyelectrolyte is examined. These results showed that the effectiveness of complex formation is strongly influenced by the process of counterion release from the polyelectrolyte chains. The radius of gyration of the complex is estimated using the Fox-Flory equation for a wormlike polymer in a theta solvent. The addition of salts in the medium accelerates the complex formation process, affecting its radius of gyration. Depending on the ratio of chain lengths a compact complex or a loosely bound elongated structure can be formed.

DPD Modelling of the Self- and Co-Assembly of Polymers and Polyelectrolytes in Aqueous Media: Impact on Polymer Science

“…As this review focuses primarily on the electrostatic co-assembly, the papers by Gonzalez-Melchor et al [161,165] deserve to be mentioned first. Using the potential of electrostatic interactions between smeared charges expressed by Equation ( 5), the authors applied the Ewald summation [166] for the enumeration of long-distance interactions and proposed a suitable alternative to the original method developed by Groot [102].…”

Computer Simulation of DNA Condensation by PAMAM Dendrimer

“…The simulation steps of 100 000 were used. For the electrostatic interaction, we used the parameters previously employed by Meneses‐Juarez et al, Slater‐type charge distribution was used with smearing coefficient β = 0.929. Ewald real forces were truncated at , real‐space convergence parameter was set as α = 0.975, for the reciprocal part, we considered the sum with a maximum vector k max = (5, 5, 5) .…”

“…All simulations were carried out with the DL_MESO 2.6 mesoscopic simulation package and the visualization was achieved by VMD . In salt‐added systems, the molar concentration of salt was calculated by , where is the number of salt ion pair and N A is the Avogadro number. The repulsive parameters between I + or I − bead and other beads are the same as that of C + or C − bead.…”

“…[44] All simulations were carried out with the DL_MESO 2.6 mesoscopic simulation package [45] and the visualization was achieved by VMD. [46] In salt-added systems, the molar concentration of salt was calculated [43] by ( / )/( )…”

DL_MESO_DPD: development and use of mesoscale modelling software

“…The articles that have not carried out simulations with dl meso dpd mainly refer to the code as available DPD modelling software. Some of these mention dl meso dpd as a code that can model coarse-grained systems [78], electrostatics [79] and many-body DPD [80], as well as an alternative to other developed DPD codes [81,82]. Other articles refer to dl meso dpd in the context of algorithmic developments -e.g.…”