Effect of solvent quality on Poiseuille flow of polymer solutions in microchannels: A dissipative particle dynamics study

Abstract

The Poiseuille flows of polymer solutions for varying quality solvents in microchannels have been simulated using dissipative particle dynamics. In particular, the velocity distributions and the polymer migration across the channel have been investigated for good, athermal, and poor solvents. The velocity profiles for all three kinds of solvent deviate from the parabolic profile, and the velocity profile of the athermal solvent falls in between the good solvent and the poor solvent. For the athermal solvent, a migration away from the wall due to the hydrodynamic interactions between the chains and the wall is observed, and a migration away from the channel center due to the different chain Brownian diffusivities is also observed. For the good solvent, because of the more stretched polymer chains, the migration away from the wall is stronger than that for the athermal solvent. However, the migration away from the channel center is not observed for good solvents. For the poor solvent, the hydrodynamic interaction within the chains is screened, and the polymer chains migrate toward the wall and appear to be absorbed by the wall.

Dissipative Particle Dynamics Simulation: A Review on Investigating Mesoscale Properties of Polymer Systems

“…realized the slip‐free condition by assigning the virtual velocity of the wall particles to the fluid particles. [ 21 ] The so‐called virtual means to give speed to the wall, but the particles on the wall are still fixed and can't move. They just carry the speed information.…”

“…reported a similar observation, the polymer model is based on the well‐known linear bead–spring polymer chain representation, and the equilibrium boundary condition model with adaptive shear correction was employed to enforce no‐slip boundary condition at the fluid–solid interface. [ 22 ] They attributed the migration of polymer chains to the Segré–Silberberg effect, [ 17,21 ] a debatable conclusion since the diffusion gradient of the Brownian motion was not considered.…”

“…It has been found that the migration of polymer chains in microchannels is related to the solvent properties as well. [ 21 ] In good solvents, the migration of polymer chains away from the wall is stronger than in poor solvents in which polymer chains migrate to and are absorbed by walls.…”