DISSIPATIVE PARTICLE DYNAMICS SIMULATIONS OF FLUID-DRIVEN POLYMER CHAINS THROUGH A MICROCHANNEL

The dynamics of fluid-driven translocation of polymers chains through a microchannel is investigated by dissipative particle dynamics (DPD) approach. Unlike implicit solvent models, this approach naturally preserves many-body energetic and hydrodynamic interactions by incorporating explicit solvent particles in this approach. An externally applied body force is exerted on each solvent particle to generate a Poiseuille flow in the microchannel, which drives the polymer chain across the narrow channel. The DPD simulations show that the polymer chain undergoes "affine-deformation", and three stages can be identified during the translocations; (1) the polymer chain initially drifts along the flow direction; (2) the polymer chain approaches the entrance of the narrow channel by undergoing a continuous conformational deformation to make its size match the pore size of the narrow channel, and part of polymer chain enter into the pore mouth of the narrow channel; (3) the polymer chain rapidly travels through the narrow channel to fulfill complete translocation. The results also show that the average translocation time steadily decreases with the increase of fluid flux. In addition, the results also demonstrate that chain rigidity exerts a considerable influence on the dynamics of polymer chain translocations, and the average translocation time steadily increases when the polymer becomes more rigid. These findings in this study may be helpful in understanding the dynamic behaviors of fluid-driven polymer and/or DNA molecules during the translocation processes.