11 Chemistry NANOTECHNOLOGY
Research for Extended Response 1
Answer each of the following questions. “Essential Chemistry” is a good reference to use. Validation - In week 9 you will be given an “in class” extended response question and you will be required to write an answer based on your home research.
1. What size are nanoparticles?
Nano particles are measured to be between 1 and 100 nanometres
Or between 1.0 × 10-9 metres and 1.0 × 10-7 metres

2. Describe what is meant by nanotechnology.
Nanotechnology is referred to as the study of nanoparticles, structures and as well as their manufacture and potential use. Nanotechnology supposedly began in 1981 when the first scanning tunnelling microscope was invented. The scanning tunnelling microscope enabled us to see individual atoms. Nanotechnology involve the ability to see and to control individual atoms and molecules.

3. Describe how nanoparticles are used in each of the following areas. You will also need to explain how the use of nanoparticles is an advantage over previous products/applications.

sunscreens:
In sunscreen, zinc oxide and titanium oxide are white opaque solids that give excellent UV protection. In previous products of sunscreen, zinc oxide and titanium oxide were used in their macro particle form (fine particles but larger then nanoparticles) they are still active an active ingredient in some sunscreens and cosmetics. A disadvantage of this product is due the visible white opaque layer that is left on the skin when the sunscreen is applied.
The use of nanoparticles in sunscreen provides us with an advantage over the past use of macro particles. This can be seen to the sunscreen being “invisible”, in the particle size range a quantum effect occurs and the zinc oxide and titanium oxide become invisible but still effective in protecting against UV exposure this effect is caused due to their particle size range.

Use of Quantum dots used in biological tracers
Nano sized particles commonly show optical effects. The varied in colours are due to the presence of different size nanoparticles of cadmium selenide, CdSe. Quantum dots are incredibly small particles. They range between 2 to 10 nanometres in diameter, which is equivalent to 50 atoms. Yes, atoms. You can't measure these things using your old school shatter proof ruler. It's this small size that gives quantum dots the unique properties to improve our tech. The colour light that a quantum dot emits is directly related to its size; smaller dots appear blue, larger ones are more red. The unique colours produced by these solutions/colloids (A colloid is a solution that has particles ranging between 1 and 1000 nanometres in diameter, yet are still able to remain evenly distributed throughout the solution) is due to the presence of quantum dots. The colours produced is due to the exposure to ultra violet light or “black light”. The light emitted/displayed is an example of quantum effect.
When in bulk, Cadmium selenide CdSe, are neither soluble in water nor exhibits this range of colours.

Carbon nanotubes (CNT’s)
Carbon nanotubes are have electrical properties which are different to the material from which they are composed. Graphite, a conductor of electricity, is composed of stacks of graphene sheets loosely bonded together. When these sheets are formed in CNT structure they show quite different patterns of conductivity to graphite. Based on their dimensions and symmetry, CNT’s can be very good conductors of electricity or semiconductors, they have a wide range of electrical properties and excellent thermal conductivity which indicates there are many potential uses for CNT’s such as Nano-sized transistors and diodes.
CNT’s have a potential advantage in the creation of computers, and maybe a potential material used to create future computers as they are able to be manufactured into thinner layers then the silicon used today and are much more efficient at carrying currents. CNT’s can result in the