Migration of polymer chains in periodically patterned slit channels: a Langevin dynamics simulation study

Abstract

The forced migration of polymer chains in heterogeneous slit channels was investigated by using Langevin dynamics simulation. The lower surface of the slit is periodically patterned by stripe α which is strongly attractive to the polymer and stripe β which is repulsive, while the upper one is purely repulsive to the polymer. Each stripe α acts as an energy trap for the polymer during the migration. At large driving force, the trap is negligible, and the polymer moves nearly freely in the channels. On the contrary, the polymer is strongly trapped and the mobility of the polymer is nearly zero at small driving force. At moderate driving force, the polymer is trapped for a finite trapping time at the interface between stripe α and stripe β, and the corresponding physical mechanisms can be well described by using the free energy landscape of polymer migration. Interestingly, the trapping time decreases with increasing the polymer length, which is attributed to the deformation of the polymer at the trapping stage.