Dynamics of Acoustically Energized Active Nematic Droplets

In a liquid crystal, the nematic phase can coexist with the isotropic phase as a dispersion of microscopic droplets. At equilibrium, these droplets adopt a spindlelike shape, known as tactoids. We report the complex dynamic behavior of nematic tactoids externally energized by an acoustic field. When activated, these tactoids exhibit a wide range of phenomena, including stretching, bending, splitting, merging, spontaneous rotation, and locomotion. We further reveal that certain pulses of acoustic energy are able to trigger a topological transformation from a tactoid to a long-lived torus-shaped droplet with elevated elastic energy. Our findings provide insights into the behavior of acoustically energized active liquid crystals in the biphasic state and suggest an approach for the manipulation of nematic droplets.