Micromaterials

Micromaterials are materials whose characteristic dimensions, structural features, or functional elements lie in the micrometer scale, typically from about 1 μm to a few tens of μm. The micrometer regime bridges conventional bulk materials and nanomaterials, with surface, grain boundary, and interface effects playing a prominent role in properties and behavior. The category includes micro-structured metals, ceramics, polymers, and composites, as well as metamaterials designed to exhibit tailored responses at small scales.

Fabrication and processing of micromaterials relies on microfabrication techniques derived from the semiconductor industry, such as photolithography, electron-beam lithography, micro-etching, and thin-film deposition. Bottom-up approaches, including chemical synthesis and self-assembly, also produce micro-scale structures. Microsystems engineering frequently employs micromaterials in MEMS devices, micro-optical components, and microfluidic systems, often integrating multiple materials and architectures on a single substrate.

Characterization and testing at the micrometer scale use specialized methods, including scanning and transmission electron microscopy, atomic force microscopy, nanoindentation, and micro-mechanical testing. Property trends at micro scales commonly exhibit size effects: strengths or hardness can rise with decreasing dimensions, while diffusion, fracture, and fatigue may follow different mechanisms due to high surface-to-volume ratios.

Applications of micromaterials span sensors and actuators in MEMS, micro-electronic packaging, optical and acoustic components, lab-on-a-chip devices, energy storage materials for microbatteries, and protective coatings for micro-scale systems. Ongoing research addresses challenges such as reproducibility, integration with macroscale parts, surface contamination, stiction, and reliability under cyclic loading.