In a study published in Nature Communications, researchers discovered a new dynamic phase in active colloidal materials that is characterized by spontaneous shockwaves that can be manipulated by using a pulsed electric field.
Spontaneous activity shockwaves in populations of Quincke rollers under temporal activity modulations. The red arrows indicate the propagation directions of two major particle waves. Insert: particle velocity map of a propagating shockwave. Red region indicates rollers in the wave front moving coherently at velocities several times of the average particle velocity. The scale bar is 100µm.
Scientific Achievement
Simulations based on 3D experimental reconstructions show the effect of curvature on domain wall formation.
Significance and Impact
The work provides fundamental insights into the macroscopic collective behavior of active roller liquids with memory in unconstrained environment. The results yield strategies for the design of active phases and microscale tunable transport in colloidal materials under temporal activity modulations.
Research Details
- Active Quincke rollers emerge due to spontaneous dielectric particle rotations in a static electric field. Temporal activity modulations via a pulsed electric field are employed to manipulate dynamic system memory and inter-particle force balances.
- Complex collective behavior is captured by a computational continuum model describing the coarse-grained dynamics of the system.