Bulk and Surface Properties of Matter Including Nanoparticles - Topic 9 Flashcards
1
Q
What is a nanometre?
A
- 1x10-9
- a millionth of 1mm
2
Q
What is the size of a nanometre in comparison to the size of an atom?
A
- the radius of an atom is about 0.1nm
- the radius of a nucleus is measured in femtometres, fm, 10-12m (or 10-3nm) metres
- a nanometre is still large compared to atomic sale - x10 bigger than atom
3
Q
What is the size of a nanometre in comparison to the size of a molecule?
A
- a water molecule is approximately 0.2nm and a Buckminster fullerenes molecule C60 is about 1nm
- Buckminster fullerene is a small nanoparticle
4
Q
What is the size of nanoparticles and what do they contain?
A
- a particle that ranges from 1-100 nanometres in size
- they contain a few hundred atoms
- nanoparticles are smaller than fine particles, which have diameters between 100 - 250nm (1 x 10-7m and 2.5 x 10-6m)
- as the side of cube decreases by a factor of 10 the SA:V increases by a factor of 10
5
Q
What does nanoscience refer to?
A
nanoscience refers to structures that are between 1-100nm in size i.e. in the order of hundreds of atoms
6
Q
What do nanoparticles show?
A
nanoparticles show different properties to the same materials in bulk - this is due to their high surface area to volume ratio
7
Q
What do nanoparticles involve?
A
fullerenes
8
Q
How are the properties of nanoparticulate materials related to their uses?
A
- A nanoparticle has different properties to the ‘bulk’ chemical it’s made from/to the same substance in normal-sized pieces, because of their high surface area to volume ratio it may also mean that smaller quantities are needed to be effective than for materials with normal particle sizes. e.g fullerenes have different properties to big lumps of carbon
- For example, titanium oxide is a white solid used in house paint and certain sweet-coated chocolates
- However, titanium dioxide nanoparticles are colourless so cannot be seen
- They are used in sunscreens to block harmful UV light
- Their high SA:V ratio makes them more effective at blocking UV light and they can be rubbed in without appearing white on the skin
- They have a high surface area to volume ratio, and therefore would make good catalysts as there would be more chance the reactants will collide with the catalyst - larger surface area for collision which increases rate of reaction
- Nanotechnology has the potential to create many new materials and devices with a vast range of applications, such as in medicine, electronics and energy production
- They can also be used to produce highly selective sensors.
- Nanotubes could make stronger, lighter building materials.
- New cosmetics, e.g sun tan cream and deodorant. They make no white marks
- Lubricant coatings, as they reduce friction. These can be used for artificial joints and gears
- Nanotubes conduct electricity, so can be used in small electrical circuits for computers
9
Q
What are tumours and what is currently used to treat them?
A
- tumours are harmful growths inside the body of a person - sometimes referred to as cancer
- currently chemotherapy is one method used to treat tumours
10
Q
How does chemotherapy treat tumours?
A
chemotherapy acts through drugs which kill tumours
11
Q
Disadvantages of chemotherapy:
A
- these drugs also destroy healthy tissue and make the patient feel very unwell
- unpleasant side-effects such as hair loss also occur
12
Q
Another method to treat tumours still using chemotherapy:
A
- if the chemicals used in chemotherapy could be delivered directly to the tumour, they could also be used in much smaller quantities
- because of this low concentration they would not harm normal healthy tissue
- the patient wouldn’t get harmful side effects and the method would be more effective
13
Q
New method of administering chemotherapy using nanoparticles:r
A
- being trialled - not tested on actual patients
- chemotherapy drugs are trapped inside a polymer coating
- the coating has in it a layer of gold nanoparticles
- these nanoparticles are only 6nm across
- they melt at a much lower temperature than bulk gold e.g. a gold bar melts at 1064 degrees C whilst the nanoparticles melt at about 700 degrees C
- when they melt, the gold nanoparticles also swell from 6nm across to over 50nm across
- these antibodies are very specific and will only bind to the tumour that is inside the patient
- it is thought that the patient being treated will be given the tiny capsules, which then travel in the bloodstream to the tumour
- when they get to the tumour, the antibodies help the capsules bind to it
- when they are bound to the tumour the capsules are bombarded with low-energy infrared laser
- the radiation heats up the capsules, the gold nanoparticles melt and then swell
- the swelling breaks open the polymer around the drugs
- the drugs are then released straight into the tumour
- because they are right next to the tumour and in high concentration, the tumour is destroyed
14
Q
What are some possible risks of some nanoparticulate materials?
A
- don’t know risks of nanoparticulate materials as they haven’t been used for long enough
- some worries are that they may be harmful to health - very small so can be absorbed into the bloodstream and change reactions in the body
- concerns about environmental impact of nanomaterials and their potential effects on global warming
- speculation about various doomsday scenarios
- concerns have led to a debate among advocacy groups and governments on whether special regulation of nanotechnology is warrants
15
Q
Physical properties of clay ceramics:
A
- solids made by baking a starting material in a very hot oven
- can be coated in a tough glaze that has an attractive shiny finish
- they are mainly silicates (compounds that contain silicone, oxygen and other elements)
- they are opaque, hard, durable, brittle and waterproof
- poor heat and electrical conductors
