4.11 Nanoparticles Flashcards
How big are nanoparticles’ diameters?
Between 1nm - 100nm
How many atoms do nano particles contain?
Between a few hundred and tens of thousands of atoms
As things get smaller, does the surface area to volume ratio decrease or increase?
Increase
Why do nanoparticles have such a large surface area to volume ratio?
As things get smaller, their volume decreases more rapidly than their surface area
Why does a larger SA to V ratio cause the properties of a material to be different when its in the form of nanoparticles to when its in bulk?
This is because, in a nanoparticle, a higher proportion of the atoms are at the surface and able to interact with substances that in the bulk material
What are 4 uses of nanoparticles where having a larger SA to V ratio is helpful? + examples
- Catalysts (e.g. to speed up reactions using less material)
- Nanomedicine (e.g. to deliver drugs directly to the inside of cells)
- Nanoparticles in electrical circuits (e.g. to make tiny computer chips)
- Silver nanoparticles for their antibacterial properties (e.g. in surgical masks to reduce chance of infection)
Why do nanoparticles work better as catalysts rather than ‘normal’ sized particles?
You’ll often need less of a material that’s made up of nanoparticles to work as an effective catalyst compared to a material made up of ‘normal’ sized particles because it’s only the exposed surface area that is important and nanoparticles have more surface area for their given volume
Why are nanoparticles used in nanomedicine?
Fullerenes could be used to cage small drug molecules and are absorbed more easily by the body than most particles. This means that they could deliver drugs right to the cells where they’re needed
What are fullerenes? (7)
- A form of carbon
- Large molecules shaped like hollow balls or tubes
- The carbon atoms in fullerenes are arranged in rings
- Their melting and boiling points are pretty high for molecular substances because they’re relatively big and bigger molecules have more intermolecular forces
- Fullerenes can form nanotubes - tiny carbon cylinders
- Nanotubes have delocalised electrons so they can conduct both electricity and thermal energy
- They also have a high tensile strength
What is using nanoparticles called?
Nanotechnology
Why are people using nanoparticles in electrical circuits?
Some nanoparticles conduct electricity, so the hope is that tiny computer chips can be made
Why are nanoparticles used for their antibacterial properties?
Because of their small size, silver nanoparticles can be infused in surgical masks and wound dressings to kill bacteria and reduce the chance of infection
Why are nanoparticles used in cosmetics such as creams and deodorants?
The small particles do their job but don’t leave white marks on the skin
Why are nanoparticles used as molecular sieves?
Small molecules can pass through pores in the material, but larger molecules get trapped on the other side of
Why are nanoparticles added to plastics to make composite materials which are used to make sports equipment?
They made the plastic much stronger and more durable, without adding much mass
What are 3 issues with nanoparticles?
- Using nanoparticles is a relatively new technology. This means that whilst lots of uses have been developed, there hasn’t yet been time to investigate the long-term impacts of nanoparticles on health
- They’re so small that they can get into cells deep within their body. Their high surface area means they could react in unknown ways with cells, leading to unexpected side-effects
- Some people think we need to regulate them more strictly and label anything that might contain nanoparticles
What is an example of a use of nanoparticles that may cause issues?
Sun cream - nanoparticles are used as they tend to be more effective at protecting our skin because the larger surface area provides more coverage against the harmful UV rays however it is not clear if the nanoparticles can get into our body or not, and if they do, whether they could be damaging our cells. We also don’t know what happens once they get washed into the sea; whether their is no evidence, its possible they could be damaging the environment
What is the field of research that focuses on nanoparticles called?
Nanoscience
What are the two potential harmful effects of sun creams that contain nanoparticles?
- They may cause harm to oceanic environments
- They may enter cells and cause damage to our DNA
