Nanoparticles

Question 1

What are the units used for materials in order of largest to smallest starting with millimetres?

Answer 1

millimetres (mm)

micrometres (μm)

nanometres (nm)

picometres (pm)

each one varies by a factor of 1000

Question 2

nanoscience

Answer 2

the study of particles between 1 nm and 100 nm

Question 3

nanoparticles

Answer 3

particles between 1 nm and 100 nm

usually contain only a few hundred atoms

Question 4

Why do things behave differently at the nanoscale?

Answer 4

surface area increases in proportion to area

the surface area:volume ratio increases

Question 5

more surface area means…

Answer 5

…more particles to react

Question 6

nanoparticulate

Answer 6

substances containing nanoparticles

Question 7

How does a nanoparticulate substance compare to the same substance in bulk (powers, lumps, sheets)?

Answer 7

it has different properties due to the large SA:V ratio

Question 8

What is the large SA:V ratio useful for?

Answer 8

nanoparticles are useful as catalysts (e.g. as coatings for self-cleaning surfaces and clothes)

Question 9

hazards and risks (4)

Answer 9

• they may be breathed in, absorbed through skin or transported into cells
• they may take a long time to break down
• they may attract toxic substances to their surfaces
• the risks to health and the environment are difficult to predict and to measure

Question 10

calculating SA:V ratio

Answer 10

surface area to volume ratio = total surface area/volume

e.g. 6/1 means a ratio of 6:1

Question 11

uses of nanoparticles (6)

Answer 11

• sunscreens
• lightweight strong materials
• drug delivery systems
• inside fridges
• inside socks
• on self cleaning surfaces

Question 12

sunscreens

Answer 12

contain nanoparticles of zinc oxide and titanium oxide which absorb harmful UV light but can’t be seen on skin

Question 13

lightweight strong materials

Answer 13

carbon nanotubes are used in tennis rackets to make them stronger

tennis balls are coated with a nano layer of butyl rubber to slow the escape of the air inside them, so they lose their pressure slower

Question 14

drug delivery systems

Answer 14

buckyballs consist of hollow balls of carbon atoms

they can be filled with drugs and made to target certain cells so that other cells aren’t harmed/the drugs are more effective

Question 15

inside fridges

Answer 15

coating the inside of a fridge with silver nanoparticles ensures that any microbe is killed and keeps the fridge clean and hygienic

Question 16

inside socks

Answer 16

silver nanoparticles in socks can kill odour causing bacteria and keep the socks fresh

socks with silver nanoparticles are also available that heal conditions such as atheletes foot, and research has shown that silver can be used to treat many other diseases

Question 17

on self cleaning surfaces

Answer 17

fabrics with nano-coatings can resist liquids and stains

windows that are self cleaning have been developed that contain nanoparticles