Dissipative particle dynamics simulations of wormlike chain adsorption onto planar walls in a pressure-driven flow

Abstract

Adsorption of wormlike chain onto planar walls in a pressure-driven flow was investigated using dissipative particle dynamics (DPD) method. The wormlike chain was modeled by the well-known bead-spring chain connected by the Marko-Siggia spring. Under static condition, the wormlike chain is adsorbed onto the wall in an extended conformation and forms trains for a strongly adsorbed wall, while sections of the chain are adsorbed and the chains form loops and tails for a weakly adsorbed wall. In the presence of pressure-driven flow, our simulations show that the chain is stretched near the wall, and the chain-wall hydrodynamic interaction would lead to the desorption of the wormlike chain. The desorption is determined by an interplay between wall-chain attractive interaction and chain-wall hydrodynamic interaction. Increasing the flow strength would increase the chain-wall hydrodynamic interaction, thereby leading to a stronger desorption. The desorption rate η of worm-like chain is found to scale as \(n\propto\dot\gamma^{0.6865}\) with shear rate \(\dot\gamma\). For a strongly adsorbed wall, all sections of wormlike chain are adsorbed with trains conformation, which causes the chain-wall hydrodynamic interaction to be screened.