Microscale

Microscale refers to dimensions on the order of micrometres, roughly 1 μm to about 1 mm. It lies between the nanoscale, where atomic- and molecular-scale phenomena dominate, and the macroscale, where bulk properties prevail. In this range, geometry, interfaces, and microstructural features increasingly govern behavior.

Key characteristics include high surface-to-volume ratios and material heterogeneity. As size decreases toward the microscale, surface and interfacial effects can alter mechanical, thermal, optical, and chemical properties compared with bulk materials. Microstructures such as grains, defects, and phase distributions influence strength, diffusion, and transport.

Characterization and fabrication at the microscale rely on specialized tools and techniques. Optical microscopy covers features near the micrometer scale, while scanning electron microscopy and transmission electron microscopy reveal submicrometer details. Atomic force microscopy measures surface topography at nanometer resolution, and micro-computed tomography provides three-dimensional imaging of internal microstructures. Microfabrication methods such as lithography, etching, and thin-film deposition are used to create microscale devices including MEMS and microfluidic components.

Applications span engineering, science, and biology. MEMS sensors and actuators, microfluidic systems for chemical analysis and biomedical work, and microoptics are prominent microscale technologies. In biology, cells typically range from about 5 to 100 μm, illustrating natural microscale phenomena. In materials science, grain sizes and defect structures are routinely characterized at this scale.

Researchers often use multiscale modeling to connect microscale processes to macroscale behavior, employing approaches such as continuum mechanics, discrete element methods, phase-field models, and coupled simulations.