Nanoparticle dispersion in porous media: Effects of attractive particle-media interactions

We investigate the effects of physicochemical attractions on the transport of finite-sized particles in threedimensional ordered nanopost arrays using Stokesian dynamics simulations. We find that weak particle-nanopost attractions negligibly affect diffusion due to the dominance of Brownian fluctuations. Strong attractions, however, significantly hinder particle diffusion due to localization of particles around the nanoposts. Conversely, under flow, attractions significantly enhance longitudinal dispersion at low to moderate P??clet number (Pe). At high Pe, by contrast, advection becomes dominant and attractions weakly enhance dispersion. Moreover, attractions frustrate directional locking at moderate flow rates, and shift the onset of this behavior to higher Pe.

Automated summary

In this study, the effects of physicochemical attractions on the transport of finite-sized particles in three-dimensional ordered nanopost arrays were investigated through Stokesian dynamics simulations. The results showed that weak particle-nanopost attractions had negligible effects on diffusion due to Brownian fluctuations. Strong attractions, on the other hand, significantly hindered particle diffusion by causing particle localization around the nanoposts. Under flow conditions, attractions enhanced longitudinal dispersion at low to moderate Péclet numbers. At high Péclet numbers, advection became dominant and attractions weakly enhanced dispersion. Additionally, attractions frustrated directional locking at moderate flow rates and shifted the onset of this behavior to higher Péclet numbers.