Flow control by smart nanofluidic channels: A dissipative particle dynamics simulation

Dissipative particle dynamics (DPD) simulation is used to investigate solvent flow through a slit channel grafted with stimuli-responsive polymer brushes. The coated channel can regulate solvent permeability when, in response to stimuli, the grafted polymer brush undergoes conformational changes. The effects of the grafting density and the chain length on the flow control capability by the smart channel have been studied. Results show that a nearly 100-fold reduction in permeation rate can be achieved with such smart channels through a proper choice of grafting parameters. Recommendations of suitable grafting parameters for optimum solvent control are given. The interplay between polymer brushes and hydrodynamic flow of the solvent is also briefly revisited. In good solvent regime, the height of the brush with low grafting density decreases with the increase of the pressure drop, but the height of the brush with high grafting density is less perturbed by the pressure drop. In the poor solvent regime, the brush height is even less perturbed by the pressure drop, regardless of the grafting density.