Aggregation of entangled active polymers

Nature provides various examples of active matter systems containing self-driven constituents capable of coordinated motion. When the individual objects are flexible, fascinating collective behavior is observed, and most studies were inspired by coherently moving bundles of flexible microtubules or clustering bacteria on two-dimensional surfaces. Recent experiments on Tubifex worms and California blackworms demonstrated that the active worms could entangle their bodies to form a worm bundle, and the structure greatly resembles an entangled passive polymer blob. However, it is largely unclear how the interplay between length, flexibility, and self-propulsion of the individual unit controls the behavior of such an entangled active polymer bundle. Using computer simulation that employs a three-dimensional model for entangled active polymer, we study the individual dynamics of the polymer and the aggregation mechanism. We consider the poly-disperse system of active polymers, and we vary the flexibility and activity of the polymer. We demonstrate that the individual activity of polymer has different effects on the collective properties of the system. We believe that our study will shed light not only on the self-organization of flexible invertebrates but also on the design principles of entangled soft robotic models.