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cDPD: A new dissipative particle dynamics method for modeling electrokinetic phenomena at the mesoscale
Mingge Deng1, Zhen Li1, Oleg Borodin2
1Division of Applied Mathematics, Brown University, Providence, Rhode Island 02912, USA.
The Journal of Chemical Physics
|October 27, 2016
Summary
We introduce a charged dissipative particle dynamics (cDPD) model for simulating electrokinetic phenomena. This method accurately captures ion transport and electrostatic interactions in complex fluids at micro- and nano-scales.
Area of Science:
- Computational physics
- Mesoscopic simulations
- Electrokinetics
Background:
- Simulating electrokinetic phenomena requires integrating fluid dynamics with electrostatic interactions.
- Existing models often face challenges in accurately capturing ion transport and boundary conditions.
Purpose of the Study:
- To develop a novel charged dissipative particle dynamics (cDPD) model for mesoscopic electrokinetic simulations.
- To incorporate ionic species transport equations into the dissipative particle dynamics (DPD) framework.
- To validate the model by comparing simulation results with theoretical solutions and experimental observations.
Main Methods:
- Developed a cDPD model by introducing extra degrees of freedom for ionic species.
- Incorporated pairwise fluxes to accurately model diffusion driven by concentration, potential gradients, and thermal fluctuations.
- Implemented an effective boundary treatment for charged surfaces in bounded systems.
- Solved the Poisson equation iteratively to obtain the electrostatic potential at each time step.
Main Results:
- The cDPD model accurately simulates the electrostatic double layer near charged surfaces, showing good agreement with mean-field theory.
- Simulations of charged parallel plates demonstrated accurate prediction of electrostatic structure and capacitance densities across varying salt concentrations.
- The model successfully simulated electro-osmotic and pressure-driven flows in micro-channels, including dilute poly-electrolyte solutions.
Conclusions:
- The proposed cDPD model provides a flexible and capable method for simulating complex fluids with electrostatic interactions at micro- and nano-scales.
- The developed boundary treatment effectively handles hydrodynamic and electrokinetic conditions for charged surfaces.
- This approach offers a powerful tool for understanding mesoscopic electrokinetic phenomena in various scientific and engineering applications.
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