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 Pećlet 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, τ des , changes with the activity. At intermediate activity, τ des displays an exponential decay with the inverse of the effective temperature, T eff ∝1 + Pe 2 /18, which is reminiscent of the mechanism of thermal activation. At higher activity, due to easily overcoming the attractive energy barrier, τ des ∝Pe −1 is found. At lower activity, a power-law dependence of τ des on the diffusion coefficient perpendicular to the surface (D ⊥ ) is observed (τ des ∼D ⊥ −1.28 ). Further, we observed a non-monotonic dependence of desorption time on the rotation diffusion coefficient D R of the monomer and found that τ des exists on a scaling relation with the chain length N, τ des ∼ N ϕ , 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.

Desorption of a self-propelling filament from an attractive surface is studied by computer simulations and the influence of activity, chain length, and chain rigidity is explored. For the flexible filament, we find three scaling regimes of desorption time vs activity with various scaling exponents. At low activity, the scaling law results from the spiral-like detachment kinetics. And at high activity, by theoretical analysis, the desorption is reminiscent of the escaping mechanism of a super-diffusive blob from a potential well at a short time scale. Additionally, the desorption time decreases first and then increases with chain length at low activity, since it is hard to form a spiral for short filaments due to the limited volume repulsion. For high activities, the desorption time approximately scales with chain length, with a scaling exponent ∼0.5, which can be explained by the theory and numerically fitting scaling law between the end-to-end distance of the “globule-like” filament and chain length. Furthermore, a non-monotonic behavior is observed between the desorption time and the chain stiffness. Desorption time slightly decreases first and then rapidly increases with stiffness due to the opposed effects of increasing rigidity on headiing-up time and leaving-away time. In contrast to traditional polymers, the scaling behavior suggests unique desorption characteristics of active polymers.

This paper was prepared for presentation at the 1999 SPE Western Regional Meeting held in Anchorage, Alaska, 26–28 May 1999.

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