Research Projects

Natural and artificial self-propelling microscopic particles are currently receiving a lot of interest from physicists and biologists alike, because of their fundamental interests and potential applications. Recently, we have demonstrated that spherical metal-dielectric Janus particles with half-metal and half-dielectric can be piloted at will in a transverse plane in a nematic liquid crystal by transducing the energy of an applied homogeneous ac electric field. These particles nucleate topological defects in the medium and break the fore-aft symmetry of the surrounding electroosmotic flows, behaving as microswimmers. Their collective behaviour defines a new class of materials termed topological active matter, where propulsion, assembly, and energy conversion are mediated by liquid crystal topology. This new class of materials, in which topological defects of nematics play a crucial role in their propulsion as well as dynamic assembly and energy conversion, have enormous potential for new directions in nonequilibrium physics and technology. In this project, we propose to synthesize and investigate anisometric metal-dielectric Janus particles (e.g., Janus rods, Janus cubes, Janus discs, Janus rings etc, see Fig.4) and study their electrophoretic propulsion and collective motility in liquid crystals. Our goal is to control their propulsion and collective dynamics by tailoring particle shape, surface asymmetry, and defect interactions. By manipulating topological features, we aim to steer the motion of individual and collective colloids with high precision. This research will chart new territory in the design of active matter systems, bridgingexperimental observations with theoretical models. Beyond its fundamental significance, the study will advance applications in targeted delivery, microfluidics, microrobotics, and active sensing technologies, leveraging the unique interplay between colloidal design and liquid crystal-mediated propulsion.

Janus particle, liquid crystals, electrophoresis, active particles, Topology, active matter