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

GQ Feng and WD Tian, MACROMOLECULES, 56, 2542-2550 (2023).

DOI: 10.1021/acs.macromol.2c01907

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 Pe ' clet 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, tau(des), changes with the activity. At intermediate activity, tau(des) displays an exponential decay with the inverse of the effective temperature, T-eff .proportional to 1 + Pe(2)/18, which is reminiscent of the mechanism of thermal activation. At higher activity, due to easily overcoming the attractive energy barrier, tau(des) proportional to Pe(-1) is found. At lower activity, a power-law dependence of tdes on the diffusion coefficient perpendicular to the surface (D-perpendicular to) is observed (tau(des) similar to D-perpendicular to(-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 tau(des) exists on a scaling relation with the chain length N, tau(des) similar to N-phi, and the scaling exponent phi decreases with the increase of activity. Our results highlight that the activity can be used to regulate the polymer adsorption and desorption behavior.

Return to Publications page