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Why do materials behave differently at sizes below 100 nanometres?
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nanotechnology
Examples from biological and mechanical realms illustrate various “orders of magnitude” (powers of 10), from 10−2 meter down to 10−7 meter.
Materials behave differently at sizes below 100 nanometres primarily due to two fundamental factors:
- Quantum Mechanical Effects: At the nanoscale, the dimensions of objects become comparable to the characteristic wavelengths of fundamental excitations, such as electrons, photons, and phonons. This proximity to the scale of quanta influences how these excitations move and interact, leading to new physical and chemical phenomena that are not apparent at larger, macroscopic dimensions.12
- Surface-to-Volume Ratio: Nanostructures possess an exceptionally large surface-to-volume ratio, meaning a significant proportion of their atoms are located at or near a surface or interface. Because surface atoms have higher average energy than those in the bulk, they exert a dominant influence on the material's properties, including increased chemical reactivity and altered mechanical or magnetic behavior.234
These changes allow materials to exhibit unique capabilities, such as enhanced strength, different melting points, or increased catalytic activity, which are exploited in fields ranging from materials science to biotechnology.42