Microscale swimming in viscosity gradients near a plane wall

In this work, we semianalytically investigate the influence of an imposed spatially linearly varying viscosity field on near wall motion of a model microswimmer (squirmer). We explore its associated phase portraits and swimming trajectories for different swimming gaits and compare them with their constant viscosity analogs. The results indicate that even simplistic ambient viscosity gradient has substantial role on near-wall squirmer motility, which provides valuable insights for understanding and controlling microswimmer motion in relatively complex biological and microfluidic systems.