Adsorption of active polymers on attractive nanoparticles

The adsorption of active polymers on an attractive nanoparticle (NP) is studied using Langevin dynamics simulations. The active polymers consist of an active Brownian particle (ABP) at the head and a subsequent passive polymer chain. The ABP experiences an active force of magnitude F_a. The interactions between the active polymer and NP are modeled as Lennard-Jones potential with a strength ε_pn. We find the critical adsorption point ε_pn* increases with increasing the active force F_a. The increment of ε_pn*, denoted as Δε_pn*, due to F_a can be expressed approximately as Δε_pn* ∝ F_a^2.5 for the restricted rotating active polymer (RRAP) where the rotation of the head ABP is restricted and Δε_pn* ∝ F_a^1.7 for the freely rotating active polymer (FRAP) where the ABP rotates freely. Meanwhile, the conformation of the adsorbed polymer, such as adsorbed trains on NP and the tail near the ABP, are also dependent on F_a. When the tail near the ABP is short, the adsorption is significantly affected by the active force. However, when the tail is long, the whole polymer can be viewed as a long tail stretched by the active force and unperturbed adsorption monomers. Simulation results show that the active force has a direct and significant effect on ε_pn* and the structure of the adsorbed active polymers.