Smart Materials by Nanoscale Magnetic Assembly

Magnetic assembly at the nanoscale level holds great potential for producing smart materials with high functional and structural diversity. Generally, the chemical, physical, and mechanical properties of the resulting materials can be engineered or dynamically tuned by controlling external magnetic fields. This Review analyzes the recent research progress on nanoscale magnetic assembly approaches toward the development of smart materials. The magnetic interactions between nanoparticles (both magnetic and nonmagnetic) and the interactions between nanoparticles and external magnetic fields are fully expatiated based on numerical simulations. In particular, the advancements of nanoscale magnetic assembly in responsive optical nanostructures, shape‐morphing systems, and advanced materials with tunable surface properties are introduced in three subsections. The key roles of magnetic interactions in nanoscale assembly toward customizable physical and chemical properties are highlighted, with focus on how to enable direct manipulation of the positional and orientational orders of the building blocks and orientational control of soft matrices through the incorporation of anisotropic magnetic structures. Nanoscale magnetic assembly, enabled by manipulating magnetic interactions between nanoparticles (both magnetic and nonmagnetic) and the interactions between nanoparticles and external magnetic fields, represents an effective platform for building smart materials including stimuli‐responsive optical nanostructures, shape‐morphing systems, and advanced materials with tunable surface chemistry.