Experimental studies on collision between self-propelling liquid crystal droplets in quasi-two-dimensional geometry

Abstract

Active droplets undergoing micellar solubilization can self-propel themselves by emitting filled micelles from their surface and are by nature anti-chemotactic. These droplets get repelled by their own trail of filled micelles or by other neighbouring droplets. We experimentally study the various types of scattering events between two such active droplets. We define different collision parameters to characterize the scattering events and monitor the time evolution of these parameters about the closest approach between the droplets. For generic oblique collisions of the droplets, we find four major types of scattering events in our experimental studies depending on the initial angle of approach, the initial Peclet numbers, the delay time, and the initial distance between the droplets. For higher Peclet number droplets, the existence of a bound state was also found.