(390b) Lose-Lose Diffusion in Complex Networks

Nanoparticle transport has gained much attention in recent years because predicting diffusion of nanoparticles is important in a variety of biomedical and pharmaceutical applications. Recent works have studied the escape of colloidal particles from porous cavities to understand the impact on the bulk diffusion coefficient of a material. However, the effect of selective attraction or repulsion throughout a porous network to tune diffusion of colloidal particles is understudied. In this work, we study a system of hard-vertex-attractive cage particles as a model porous network and show how to tune diffusion with a combination of particle size, and central attraction/repulsion between the diffusing particles and cage centers. The diffusing probe particles are WCA spheres that are repulsive with the edges of the cages and either attractive or repulsive with the cage centers. We find that particle size sets the maximum diffusion coefficient and that both attraction and repulsion between the cages and the WCA probes lowers the diffusion coefficient (a trend we call Lose–Lose diffusion). Finally, we show that our system can be modelled via a continuous time random walk with the addition of repulsive moves for our repulsive cages. We thereby show that central attraction and repulsion in porous networks are valuable tools to decrease macroscopic diffusion, and that particle size sets the maximum diffusivity of particles within our porous networks.