Nanoscience (AQA GCSE Chemistry): Revision Notes
Nanoscience
What is nanoscience?
Nanoscience is the study of very tiny structures called nanoparticles. These particles contain only a few hundred atoms. They behave differently from the same materials in larger amounts because they have a much higher surface area to volume ratio.
The unique properties of nanoparticles arise from their incredibly small size - they exist at the boundary between individual atoms and bulk materials, giving them special characteristics that neither atoms nor larger materials possess.
Size of different particles
Scientists group particles by size:
- Atoms: About 0.2 nm diameter (the smallest building blocks)
- Nanoparticles: 1-100 nm diameter (a few hundred atoms)
- Fine particles (PM₂.₅): 100-2500 nm diameter
- Coarse particles (PM₁₀): 2500-10000 nm diameter (includes dust)
Key fact: One nanometre (1 nm) is one millionth of a millimetre. That's incredibly small!
Surface area to volume ratio
This is why nanoparticles are so special. As particles get smaller, their surface area to volume ratio gets much bigger.
Worked Example: Surface Area to Volume Ratio
Let's compare two cubes to understand this concept:
-
A large cube (10×10×10 units):
- Volume = cubic units
- Surface area = square units
- Ratio =
-
A tiny cube (1×1×1 unit):
- Volume = cubic unit
- Surface area = square units
- Ratio =
The smaller cube has 10 times more surface area compared to its volume!
This means nanoparticles have much more surface area exposed to react with other substances. This makes them very useful as catalysts (substances that speed up chemical reactions).
Uses of nanoparticles
Nanoparticles are used in many areas:
- Medicine: To deliver drugs directly to specific parts of the body
- Medicine: As artificial skin for treating burns
- Electronics: In computer components
- Cosmetics: In makeup and skincare products
- Suncream: To protect skin from UV rays better
- Fuel cells: As catalysts to make reactions happen faster
- Deodorants: To kill bacteria more effectively
Scientists are still researching new uses for nanoparticles. Smaller amounts of material are needed because they're so effective due to their high surface area to volume ratio.
Real-world example - suncream
Worked Example: Nanoparticles in Suncream
Suncream with nanoparticles works better than normal suncream. The tiny particles cover more skin surface area with the same amount of product. This gives better protection from the sun's harmful UV rays.
However, there are concerns about nanoparticles getting into living cells and potentially causing damage to DNA.
Special nanoparticles - buckyballs
Buckyballs are special nanoparticles made entirely of carbon atoms. They're shaped like football balls. Scientists think they could be used to deliver medicines directly into the human body because of their unique structure.
Remember!
Key Points to Remember:
- Nanoparticles are 1-100 nm in size with just a few hundred atoms
- They have a very high surface area to volume ratio compared to larger particles
- This high ratio makes them excellent catalysts and very effective in small amounts
- They're used in medicine, electronics, cosmetics, and many other areas
- New applications are being discovered all the time as research continues