Controlling the Crystal Structure of Anisotropic Particles Via Depletion

The depletion interaction is one way to induce aggregation in colloidal systems due to the way that the depleting polymers will maximize their entropy when the colloids aggregate. Self-assembly studies of monodisperse hard particle systems have shown that shape plays a vital role in assembly behavior due to the effect of directional entropic forces. Though there are several reports of depletion-controlled self-assembly of anisotropic particles, systematic study and predictive theories are still lacking. Here, we report on Monte Carlo simulations of anisotropic hard particles with depletion effects using the penetrable hard sphere model. We show that depletion size and concentration can be used to control the assembly of unique three-dimensional crystal structures. We further show that depletion can be used to reconfigure anisotropic particles between different crystal structures. We believe that these properties in systems with depletion can be exploited to produce new, adaptable materials.