The depletion interaction due to ring and linear polymers

The presence of non-adsorbant macromolecules in a colloidal solution gives rise to an attraction between colloids termed depletion interaction. Inspired by a recent experimental and computational study, we investigate the difference of depletion interaction induced by ideal ring and linear polymers. Combining various theoretical results, we found that a single, topology-dependent length-scale controls the depletion interaction strength. In addition, we show how to compute this quantity using structural information, that is via Molecular Dynamics simulations. Within finite-size effects, the simulations are in agreement with the theory.