Desorption of a Flexible Polymer with Activity from a Homogeneous Attractive Surface

Abstract

The interfacial behavior of a flexible polymer with activity, which is named active Brownian polymer (ABPO), is studied by Langevin dynamics simulations. On the dependence of the adsorption strength and activity characterized by the Péclet number (Pe), the polymer displays two typical states on the surface: adsorption and desorption states. We find that the diffusion behavior of ABPO that is parallel to the surface yields the “active Rouse model” and the activity causes the adsorption–desorption transition at a certain adsorption strength. Particular attention is given to how the desorption time, τdes, changes with the activity. At intermediate activity, τdes displays an exponential decay with the inverse of the effective temperature, Teff ∝1 + Pe2/18, which is reminiscent of the mechanism of thermal activation. At higher activity, due to easily overcoming the attractive energy barrier, τdes ∝Pe–1 is found. At lower activity, a power-law dependence of τdes on the diffusion coefficient perpendicular to the surface (D⊥) is observed (τdes ∼D⊥–1.28). Further, we observed a non-monotonic dependence of desorption time on the rotation diffusion coefficient DR of the monomer and found that τdes exists on a scaling relation with the chain length N, τdes ∼ Nϕ, and the scaling exponent ϕ decreases with the increase of activity. Our results highlight that the activity can be used to regulate the polymer adsorption and desorption behavior.