Injection of a Self-propelled Polymer into a Small Circular Cavity

The injection of a polymer chain into a small circular cavity under tangential self-propelled force is studied by using Langevin dynamics simulation. Results indicate that the injection dynamics of the active polymer shows strong correlation with the polymer conformation inside the cavity depending on the polymer rigidity (k_b). The injection time τ varies nonmonotonously with increasing k_b, and reaches its minimum at k_b*. When k_b is small (k_b ≪ k_b*), the polymer is nearly random coil in the cavity, and spends a long time at the final stage of the injection process due to the large repulsion between monomers inside the cavity. When k_b is moderate (k_b ∼ k_b*), the part of polymer inside the cavity forms spiral configuration under the tangential active force, and the whole polymer moves synchronously with a constant velocity during the injection process, leading to a small injection time. When k_b is large (k_b ≫ k_b*), the polymer is nearly straight at the initial stage of the injection process, and takes a long time to bend itself, leading to a large injection time.