microparticles

Microparticles are solid particles whose size falls in the micrometer range, typically from about 1 micrometer to 1000 micrometers in diameter (1 millimeter). They can be natural or engineered and may consist of polymers, metals, ceramics, or composite materials. Their properties depend on size, shape, porosity, and surface chemistry, which influence their behavior in fluids, on surfaces, or in biological systems.

Production methods include mechanical size reduction (milling or grinding) of larger solids, spray drying, atomization, precipitation, and emulsion polymerization. Other approaches build particles from solution or melt, often with control over size distribution, crystallinity, and surface coatings to tailor compatibility and reactivity.

Characterization and properties: Size distributions can be measured by laser diffraction or sieving; morphology by microscopy; porosity and surface area by BET or related methods. Zeta potential and surface charge affect suspension stability. Shape, roughness, and porosity influence flow, packing, and interactions with chemicals or living tissues.

Applications: Microparticles find use in drug delivery and therapeutics, as cosmetic pigments and fillers, in environmental remediation for adsorption of contaminants, as catalysts or catalyst supports, in electronics and energy storage, and as reinforcing fillers in polymer or ceramic composites.

Safety and environment: Handling powders requires controls to limit inhalation and dermal exposure. Toxicity depends on material, size, surface chemistry, and dose. Environmental considerations include persistence and, for plastics, potential microplastic release; regulations govern labeling, handling, and disposal.