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

TL;DR

This study experimentally investigates collision behaviors of self-propelling liquid crystal droplets in quasi-two-dimensional settings, revealing four main scattering types and the formation of bound states at higher Peclet numbers.

Contribution

It provides a detailed experimental analysis of collision dynamics and introduces a classification of scattering events based on initial conditions and parameters.

Findings

Four main scattering types depending on initial approach angle and parameters

Existence of bound states at higher Peclet numbers

Characterization of collision parameters and their evolution

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.