Mesoscopic simulation of entanglements using dissipative particle dynamics: Application to polymer brushes

Abstract

We use a simple spring-spring repulsion to model entanglements between polymers in dissipative particle dynamics (DPD) simulations. The model is applied to a polymer brushes system to study lubrication. We demonstrate that this method leads to mechanical equilibrium in polymer brushes using the normal DPD time step. The number of bond crossings is calculated to provide a quantitative description of the entanglement. We demonstrate that it is possible to avoid 99% of the bond crossings with the values of spring-spring repulsion that can be used without significantly decreasing the time step. A shear force is applied to the system to study the effect of the decrease in the bond crossings on the structure and rheological properties of the brushes. In particular, we show how the friction coefficient increases with the decrease in the bond crossings of the polymers.

Challenges in Multiscale Modeling of Polymer Dynamics

“…The estimated entanglement length of DPD polymers is found to be consistent with the classical MD simulations [247,248]. These works build on studies by Goujon et al [249], who developed a repulsive potential between segments [250] in DPD simulation to avoid bond crossing. The blob model has been adopted to study the dynamic and rheological properties of PE and poly(ethylene-alt-propylene) (PEP) polymers [84,85,241].…”

Friction coefficient and viscosity of polymer brushes with and without free polymers as slip agents

“…However, the erukamide chains we have modeled are too short to display reptation -like motion, therefore entanglement effects are not present here [25].…”

Linear and non-linear dynamics of entangled linear polymer melts by modified tunable coarse-grained level Dissipative Particle Dynamics

“…If both conservative and repulsive entanglement forces are neglected, polymer chains can move freely, so in order to consider the steric constraints, that is, to prevent bondcrossing from occurring, we follow the model of Goujon et al, [17][18][19] as mentioned before; in this, the authors prevented the effect by introducing entanglement forces,…”

“…Nikunen et al 17 developed a method to avoid bond crossing in DPD by adjusting parameters for the conservative force. Finally, Goujon et al [17][18][19] applied Kumar and Larson's method 15 to prevent bond crossing of polymer brush systems under flow. In our work we successfully applied the methodology by Goujon et al, 17 as will be shown later.…”