Brownian dynamics simulations of tracer diffusion and dynamics in polyelectrolyte gels
Advancing the chemical engineering fundamentals
Transport Phenomena in Porous/Granular Media - I (T2-7a)
Keywords: Brownian dynamics simulation, gel network, tracer diffusion, mesoscopic scale.
Theoretical investigations on tracer diffusion in polyelectrolyte gels are scarce as compared to those for static properties. In this paper, Brownian dynamics simulations are employed to study the diffusion behavior of charged tracer particle in a polyelectrolyte gel network, which can be either rigid or flexible. A coarse-grained bead-spring lattice model is used along with a truncated Lennard-Jones potential representing the excluded volume effect and a screened electrostatic interaction accounting for charge effect. Owing to the limitation of present computer power, such a mesoscopic approach is inevitable to handle long time dynamics. The tendency of mean square displacement and diffusion coefficient with varying bead size, spring constant and charge condition is investigated. The short time diffusion coefficient is obviously different from the long-time diffusion coefficient, and the self-diffusion coefficient of tracer particle decreases as volume fraction, spring constant and charge density of the cubic lattice increased, respectively. The diffusion behaviors of tracer particle have significant differences between the case in which the tracer particle and gel beads are reversely charged and the case in which they have the same sign. The explanation of the behavior of tracer particle self-diffusion in the lattice model is also discussed in this paper.
Presented Tuesday 18, 11:20 to 11:40, in session Transport Phenomena in Porous/Granular Media - I (T2-7a).
