Topological defects and electro-convective flows in anisotropic fluids: A microfluidic platform for nano-objects tunable structuring

Anisotropic fluids are a class of soft materials that offer wide possibilities for engineering a small scale laboratory; their physical properties can be manipulated on short length scale by appropriate confining conditions and external stimuli leading the systems across fascinating phenomena. In this work, two of these phenomena are combined to create a microfluidic platform for reconfigurable nanoparticles (NPs) patterning: the formation of topological defects and the electrically controlled convective flows. Here, the nanoscopic environments created by defects within liquid crystals have been used as linear nano-reservoirs of NPs. Afterwards, virtual channel flows that connect the linear reservoirs have been created by exploiting electro-convective rolls. The reported results reveal a strategy for managing nanometric objects based on anisotropic fluids and connected phenomena, proposing an unconventional microfluidic device characterized by switchable and contactless micro-channels.