Reconfiguring active particles by electrostatic imbalance.

  title={Reconfiguring active particles by electrostatic imbalance.},
  author={Jing Yan and Ming Han and Jie Zhang and Cong Xu and Erik Luijten and Steve Granick},
  journal={Nature materials},
  volume={15 10},
Active materials represent a new class of condensed matter in which motile elements may collectively form dynamic, global structures out of equilibrium. Here, we present a general strategy to reconfigure active particles into various collective states by introducing imbalanced interactions. We demonstrate the concept with computer simulations of self-propelled colloidal spheres, and experimentally validate it in a two-dimensional (2D) system of metal-dielectric Janus colloids subjected to… 

Spontaneous self-propulsion and nonequilibrium shape fluctuations of a droplet enclosing active particles

Active particles, such as swimming bacteria or self-propelled colloids, spontaneously assemble into large-scale dynamic structures. Geometric boundaries often enforce different spatio-temporal

Manipulation of emergent vortices in swarms of magnetic rollers

This work shows that magnetic colloidal rollers spontaneously self-organize into unconfined macroscopic vortices under a magnetic field, which can be used to transport inert particles across a flat surface.

Active apolar doping determines routes to colloidal clusters and gels

The concept of “active doping” is introduced and a few light-activated apolar units can be used to rapidly trigger the formation of solid clusters and gels composed of passive colloidal particles, providing a pathway toward the rapid engineering of mesoscopic gels and clusters via active colloidal doping.

Hydrodynamically Controlled Self-Organization in Mixtures of Active and Passive Colloids.

Active particles are known to exhibit collective behavior and induce structure in a variety of soft-matter systems. However, many naturally occurring complex fluids are mixtures of active and passive

Guiding Self-Assembly of Active Colloids by Temporal Modulation of Activity.

Self-organization phenomena in ensembles of self-propelled particles open pathways to the synthesis of new dynamic states not accessible by traditional equilibrium processes. The challenge is to

Inhomogeneous assembly of driven nematic colloids.

An analysis of the nonequilibrium assembly of colloidal particles dispersed in a nematic liquid crystal reveals a linear density profile that can be tuned with the field frequency, and a bond-orientational order that reaches a maximum at intermediate packing densities, where elastic effects are minimized.

Shape-directed dynamics of active colloids powered by induced-charge electrophoresis

Focusing on active colloids powered by induced-charge electrophoresis, theory and simulation are used to show how the shape of a colloidal particle can be rationally tailored to specify complex motions powered by simple energy inputs.

Arrested-motility states in populations of shape-anisotropic active Janus particles.

The emergence of large-scale collective phenomena from simple interactions between individual units is a hallmark of active matter systems. Active colloids with alignment-dominated interparticle

Emergence of self-organized multivortex states in flocks of active rollers

It is shown by experiments and computational modeling that concentrated magnetic rollers self-organize into multivortex states in an unconfined environment and that the neighboring vortices more likely occur with the opposite sense of rotation.



Mesoscopic turbulence and local order in Janus particles self-propelling under an ac electric field.

To elucidate mechanisms of mesoscopic turbulence exhibited by active particles, an experimental system with dense suspensions of asymmetrical colloidal particles (Janus particles) self-propelling on a two-dimensional surface under an ac electric field is realized.

Hydrodynamics of soft active matter

This review summarizes theoretical progress in the field of active matter, placing it in the context of recent experiments, and highlights the experimental relevance of various semimicroscopic derivations of the continuum theory for describing bacterial swarms and suspensions, the cytoskeleton of living cells, and vibrated granular material.

Linking synchronization to self-assembly using magnetic Janus colloids

This work combines synchronization-selected microtubes of Janus colloids, micron-sized spherical particles with different surface chemistry on their opposing hemispheres, to create synchronization-induced structural transition that offers various applications based on the potential to form, disintegrate and fine-tune self-assembled in-motion structures in situ.

Flocking at a distance in active granular matter.

It is reported here that millimetre-sized tapered rods, rendered motile by contact with an underlying vibrated surface and interacting through a medium of spherical beads, undergo a phase transition to a state of spontaneous alignment of velocities and orientations above a threshold bead area fraction.

Spontaneous motion in hierarchically assembled active matter

These observations exemplify how assemblages of animate microscopic objects exhibit collective biomimetic properties that are very different from those found in materials assembled from inanimate building blocks, challenging us to develop a theoretical framework that would allow for a systematic engineering of their far-from-equilibrium material properties.

Directed Self-Assembly Pathways of Active Colloidal Clusters.

This work assembling rotating chiral clusters of various sorts, their structures consisting of active particles wrapped around central "hub" particles, which self-assemble from the competition between standard energetic interactions and the need to be stable as the clusters rotate as the energy source is turned on, and fall apart when the energy input is off.

From Clarkia to Escherichia and Janus: the physics of natural and synthetic active colloids

In these lectures, a pedagogical introduction to the physics of single-particle and collective properties of active colloids, focussing on self propulsion is given.

Living Crystals of Light-Activated Colloidal Surfers

A form of self-organization from nonequilibrium driving forces in a suspension of synthetic photoactivated colloidal particles is demonstrated, which leads to two-dimensional "living crystals," which form, break, explode, and re-form elsewhere.

Magnetic manipulation of self-assembled colloidal asters.

It is shown that a magnetic colloidal suspension confined at the interface between two immiscible liquids and energized by an alternating magnetic field dynamically self-assembles into localized asters and arrays of asters, which exhibit locomotion and shape change.

A colloidal model system with an interaction tunable from hard sphere to soft and dipolar

This work demonstrates a charge- and sterically stabilized colloidal suspension—poly(methyl methacrylate) spheres in a mixture of cycloheptyl (or cyclohexyl) bromide and decalin—where both the repulsive range and the anisotropy of the interparticle interaction potential can be controlled.