Swimming upstream: self-propelled nanodimer motors in a flow†

The dynamics of chemically-powered self-propelled nanodimer motors in a fluid flow are investigated. The dimer motors are confined to move in a square channel within which a Poiseuille-like fluid flow exists. The flow direction is opposite to that of the nanomotor’s directed motion. Simulations of the dynamics are carried out using mesoscopic hybrid molecular dynamics/multiparticle collision dynamics. The simulations of the Poiseuille flow in a square channel are in accord with analytical results for this type of flow. The upstream swimming of the nanodimers is studied as a function of the fluid flow velocity, channel width and interaction strength with the walls and fluid particles. The channel width determines the flow behavior in the channel, while the interaction potentials between the noncatalytic monomer and solvent molecules control the self-propulsion velocity of the nanodimer.