Magnetic Click Colloidal Assembly

We introduce a new class of spherical colloids that reversibly
self-assemble into well-defined nonlinear structures by virtue of
“magnetic patches”. This assembly is driven by tunable
magnetostatic binding forces that originate from microscopic permanent
magnets embedded underneath the surface of the particles. The resulting
clusters form spontaneously in the absence of external magnetizing
fields, and their geometry is determined by an interplay between magnetic,
steric, and electrostatic interactions. Imposing an external magnetic
field enables the clusters to unbind or change their geometry allowing,
in principle, the creation of materials with a reconfigurable structural
arrangement.