Magnetic Click Colloidal Assembly

Stefano Sacanna*†, Laura Rossi‡, and David J. Pine†

^† Center for Soft Matter Research, Department of Physics, New York University, 4-6 Washington Place, New York, New York 10003, United States

^‡ Van’t Hoff Laboratory for Physical and Colloid Chemistry, Debye Institute for Nano-materials Science,Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands

J. Am. Chem. Soc., 2012, 134 (14), pp 6112–6115

DOI: 10.1021/ja301344n

Publication Date (Web): March 27, 2012

Copyright © 2012 American Chemical Society

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.