Related Experiment Video
Updated: Apr 21, 2026

Preparation of Janus Particles and Alternating Current Electrokinetic Measurements with a Rapidly Fabricated Indium Tin Oxide Electrode Array
Published on: June 23, 2017
Rotating crystals of magnetic Janus colloids
1Departments of Materials Science and Engineering, Chemistry and Physics, University of Illinois at Urbana-Champaign, 1304 W. Green St., Urbana, IL 61801, USA. sgranick@illinois.edu.
Abstract:
Monodisperse magnetic colloids are found to self-assemble into unusual crystals in the presence of rotating magnetic fields. First, we confirm a predicted phase transition (S. Jäger and S. H. L. Klapp, Soft Matter, 2011, 7, 6606-6616), directly coupled to the dynamic transition of single particle motion, from a disordered state to a hexagonal crystal. Next, going beyond what had been predicted, we report how hydrodynamic coupling produces shear melting, dislocations, and periodically mobile domain boundaries. These uniform magnetic colloids, whose structures are modulated in situ using the protocols described here, demonstrate a strategy of stimulus-response in the colloid domain with potential applications.
Related Concept Videos
Colloidal precipitates
Colloids and Suspensions
Colloids
Crystal Field Theory - Octahedral Complexes
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...
The Colloidal State
Crystal Growth: Principles of Crystallization
Initiating crystallization involves manipulating the concentration of the solute and the temperature of the solution. Since crystal growth occurs when the ratio of concentration and solubility of the solute in the solvent...

