nanosize

Nanosize refers to dimensions on the nanometer scale, typically from about 1 to 100 nanometers. Sizes smaller than about 100 nm can lead to unique physical and chemical properties due to quantum effects and a large surface area to volume ratio.

Objects described as nanosize include nanoparticles (spheres), nanorods, nanotubes, nanoplates, and nanofilms. The term is often used to denote the small dimensions of these structures; in practice nanosize is closely related to nanoscale, but emphasizes the actual size in nanometers.

Measurement and characterization involve microscopy and scattering techniques. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) reveal shape and size; atomic force microscopy (AFM) provides surface topography. Dynamic light scattering (DLS) gives size distribution in suspensions; X-ray diffraction (XRD) assesses crystallinity and phase.

Synthesis and control methods are broadly categorized as top-down approaches (lithography, milling) and bottom-up approaches (chemical synthesis, self-assembly). Achieving uniform size, shape, and surface chemistry is a major focus to tailor properties.

Properties and applications: nanosized materials often show high surface area-to-volume ratio, which enhances reactivity, strength, or catalytic activity. Quantum confinement can affect optical properties. Applications include medicine (drug delivery, imaging), electronics and plasmonics, energy storage and conversion, coatings, and sensors.

Safety and regulation: nanoscale materials may interact with biological systems and the environment in distinct ways, raising toxicity and persistence concerns. Responsible development includes risk assessment, safety data, exposure controls, and adherence to evolving regulatory guidelines.