Nanowerk February 23, 2022
Self-organized vortex of rotating microparticles in a fluid will reverse direction when an electric stimulus is interrupted and then reapplied with the same orientation. A team of researchers in the US (Argonne National Laboratory, Northwestern University) investigated how these collective self-assembled states can be controlled and manipulated, and what would happen when they stopped and then restarted the field fueling the motion of the particles. They found that the particles’ relative positions created a kind of distributed collective memory that caused them to begin to rotate in the opposite direction. They found that this phenomenon was driven by an interplay between electrostatic and hydrodynamic forces. According to the researchers the reversal of the system could be useful for materials that work on a toggle system, like microfluidic pumps or other kinds of biomechanical switches, for instance for drug delivery…read more. TECHNICAL ARTICLEÂ
Vortex chiral state reversal induced by a temporal modulation of activity. Credit: Nature Physics volume 18, pages154–159 (2022)Â