Favorable partition of nanoswimmers toward a confined slit

The partition of nanoswimmers between a narrow channel and a reservoir is explored by dissipative particle dynamics. In contrast to passive colloids, nanoswimmers prefer to stay in the slit rather than in the reservoir for sufficiently large active force (Fa) or run time (τ). The partition ratio (φ) increases with Fa and τ. Interestingly, as the slit height decreases, φ grows accordingly until the confinement effect dominates. Three types of the concentration profile in the slit are identified as a consequence of the competition between surface accumulation and entropic barrier.