Active structuring of colloids through field-driven self-assembly

In recent years self-assembly has become progressively more active, i.e. the focus of research gradually has shifted towards field-manipulation of matter in order to form temporary states rather than creating static architectures. The desire for time-programmed control of materials certainly originates from the unmatched complexity of natural systems that orchestrate multiple components across length scales. Although artificial self-assembly still lacks control comparable to natural systems, there has been impressive progress in a concerted approach from physicists, chemists, biologists, and engineers. This review summarizes the current trend in colloidal assembly advancing from static assembly of isotropic particles towards active structuring of anisotropic particles with heterogeneous (patchy) surfaces, and ultimately, to complex behavior in dissipative dynamic systems. We focus both on the formation of static structures and on temporary states due to response to magnetic, electric, or optic stimulation. We give examples of nano- and microparticle assembly where the temporary state may adopt equilibrium order or a continuously changing dynamic pattern.