Relational Analysis Between a Calcium Alginate Self-Propelled Surfer and the Marangoni Convection for the Application of Waterborne Transporters

An oil droplet dropped into aqueous solution self-propels spontaneously in random directions. In our previous studies, we have discovered that a rigid exoskeleton applied to a droplet determines the propulsion direction by restricting the formation of the surface tension gradient to generate Marangoni convection around and inside the self-propelled droplet. This study investigates the relationship between Marangoni convection and the propulsion characteristics of calcium alginate self-propelled surfers with rigid exoskeletons. By designing and testing various exoskeleton geometries, we demonstrate that the length, width, and opening area of the exoskeleton significantly influence the motion dynamics of the surfers. These findings provide valuable insights into optimizing exoskeleton designs for applications in micro-robotics, targeted drug delivery, and environmental remediation.