(383d) Light-Activated Janus Colloids within Thermotropic Liquid Crystals

The design of self-propelled systems has become crucial to the material sciences for engineering novel technologies. Studies on external fields-activated colloids have been mainly done within simple liquids; however, we have gone one step forward by using a structured material that displays liquid crystalline mesophases as the host medium. In this work, we use Janus silica particles half-coated with titanium, immersed in a thermotropic liquid crystal (LC). Its mobility is triggered as a consequence of inducing an uneven localized LC nematic-isotropic phase transition after the titanium side absorbs light. We use particle tracking analysis to examine the optical response of the LC that underlies the particles’ trajectories. Our results include the report of different trajectories, mean squared displacements and speeds computed at different light powers. Unlike non-structured liquids, here we present a discussion of the involved surface, elastic and Landau-de Gennes interactions that permit the particles to super-diffuse in the LC. Additionally, ongoing machine-learning based simulations will help us to test our physical model. This research contributes to a better understanding of micro-swimmers’ trajectories immersed in highly structured media, which is a topic of importance in the physical, material and biological sciences.