What is nanotechnology?
Nanotechnology is the science of designing and using materials on the scale of nanoparticles, defined as particles between 1 and 100 nanometres (nm). One nanometre is 1 × 10−9 m. At this size, materials behave differently from their bulk form.
Why nanoparticles are special
The key reason is their very large surface area to volume ratio. When a solid is divided into tiny pieces, the total surface area increases enormously while the volume stays the same. A larger exposed surface means nanoparticles are far more reactive and make excellent catalysts, needing only small amounts. Their tiny size can also change colour, strength and electrical behaviour compared with the bulk material, opening up uses that the ordinary solid cannot provide.
Key idea
Smaller particle → larger surface area to volume ratio → greater reactivity and catalytic power. This single idea explains most industrial uses of nanotechnology.
Industrial applications
- Medicine: nanoparticles carry drugs directly to diseased cells (targeted drug delivery).
- Electronics: smaller, faster microchips and better computer memory.
- Cosmetics: titanium dioxide (TiO2) and zinc oxide (ZnO) nanoparticles in sunscreen block UV yet stay transparent.
- Materials: carbon nanotubes are extremely strong and light, used in sports gear and composites.
- Coatings: self-cleaning, water-repellent and scratch-resistant surfaces.
- Environment: nano-filters and catalysts help clean polluted water and treat waste gases.
Worked example
Why is a nano-sized catalyst more effective than the same mass of large lumps? Dividing the metal into nanoparticles greatly increases the total surface area available for reaction, so more reactant molecules collide with the catalyst and the rate rises.
Remember
- Nanoparticle size: 1–100 nm.
- Large surface area to volume ratio = key property.
- Possible risks: nanoparticles may enter cells and affect health or the environment.