Diffusiophoretic Motion of an Isolated Charged Soft Particle

The diffusiophoretic motion of a uniformly distributed charge soft particle suspended in an infinite medium of electrolyte solution is studied in this paper. The resulted nonlinear electrokinetic equations governing the diffusiophoretic motion are solved numerically with a pseudo-spectral method based on Chebyshev polynomials. In particular, the convection contribution of the ion flux and the polarization effect are taken into account. Key parameters of electrokinetic interest are examined for their respective effect on the particle motion, and the results presented here show the particle diffusiophoretic mobility deviates significantly from the analytical prediction using linear Poisson-Boltzmann equation. Meanwhile, it is also found that a soft particle may reverse its direction with a high surface charge condition of the hard core, which significantly influences the diffusiophoretic motion. These results provide more information about the general electrokinetic behavior of a soft particle such as sphere polyelectrolyte brushes, polymer-coated colloidal particles and other engineered nanoparticles (ENPs), which has a great potential in treating systems of biochemical or microfluidic interests.