All FAQs have been provided by University of Sheffield
1. What is nanotechnology?
Nanotechnology is an area of Science that is concerned with the control and manipulation of matter on the molecular scale. This scale is often measured in nanometres, hence the nano in nanotechnology.
2. How small is a nanometre?
If you take an average 4 year old child with a height of 1m and then shrink them by a factor of 1000, they would then be the size of an ant (or a millimetre). If you shrink them again by a factor of 1000, they would be the size of a red blood cell (or a micrometre). We need to shrink them once more by a factor of 1000 to reach a scale measured in nanometres.
3. What is the science behind Catalytic Clothing?
Catalytic Clothing harnesses the power of a photocatalyst to break down air borne pollutants. A catalyst is a term used to describe something that makes a reaction proceed at a greater rate but isn’t actually consumed during that reaction. A photocatalyst gains the energy it needs to be active from light.
4. Where do the pollutants come from?
The two biggest sources of air borne pollutants are industry and motor vehicles. Although the majority of the pollutants are prevented from reaching the air, using technology such as catalytic converters, some do escape. It is these pollutants that Catalytic Clothing will break down.
5. How are the pollutants broken down?
When the light shines on the photocatalyst, the electrons in the material are rearranged and they become more reactive. These electrons are then able to react with the water in the air and break it apart into 2 radicals. A radical is an extremely reactive molecule. These radicals then react with the pollutants and cause them to break down into non-harmful chemicals.
6. What happens to the pollutants after they’ve been broken down?
The Catalytic Clothing technology is designed to breakdown the pollutants straight away. However, some pollutants may become attached without being broken down. In this case, the pollutants will be washed off during subsequent laundering. This actually already happens with normal clothing.
7. Is this technology used in any other products?
Photocatalysts have been incorporated into several commercially available products that possess de-polluting properties. These products include paints, cements and paving stones.
8. How is the technology delivered to the surface of the clothing?
The photocatalyst is delivered to the surface of the clothing during the traditional laundry procedure as an additive within a standard product such as a fabric conditioner. The active agent is packaged within a shell that is attracted towards, and subsequently binds to, the surface of the clothing during the washing cycle.
9. Why do we need mass participation to produce a noticeable reduction in the level of pollution?
Although any garment that is treated with the product becomes active, a single garment is only able to remove a small proportion of the air borne pollutants. Therefore, a large number of individuals, all acting together, is required to produce a noticeable reduction in the level of pollution.
10. How many people would need to participate to produce a noticeable reduction in the level of pollution?
An estimate of the required level of uptake for the Catalytic Clothing indicates that a significant reduction in the level of air borne pollutants in a large city such as London could be achieved if, for every metre of pavement width, 30 people wearing Catalytic Clothes walked past each minute.
11. Would someone wearing Catalytic Clothing be at a greater risk of exposure to pollutants?
No. The Catalytic Clothing technology won’t actively attract any pollutants. Instead, it will break down anything that comes within very close proximity of the photocatalyst’s surface.
12. How would society benefit if Catalytic Clothing was widely introduced?
Exposure to air borne pollutants presents a risk to human health and also has a detrimental effect on ecosystems and vegetation. Air pollution is currently estimated to reduce the life expectancy of every person in the UK by an average of 7-8 months. The widespread introduction of Catalytic Clothing would dramatically reduce the level of air borne pollutants, thereby improving the quality of life for all members of society.
13. Can any material be used?
Each type of material will need to be tested separately for efficacy and adhesion, but it is our aim to make this technology deliver to all fabric types eventually. We have started with one of the most commonly used materials, cotton.
14. What will be the cost of using this domestically?
It is hard to say at this stage and will depend on whether it ends up as an additive, or a product in its own right. As mass use will have the most impact on air quality, clearly the cost has to be as competitive as possible.
15. Are there any “down sides”?
We will discover these as the research continues and try to create solutions as we go.
16. How can you reassure people that it will be safe?
The product will go through full life cycle analysis as any other new product being brought to market. All H&S aspects will be independently validated and just like a new medicine, or new skin care product, all the usual legal requirements will be met ahead of the product reaching the supermarket shelves.
17. When might it be available?
We are aiming for two years if all goes to plan!
18. How can you tell if it’s working?
Most major cities and towns have some from of air quality monitoring stations already in place. Those monitors record the levels of a range of major pollutants, such as NOx and VOC’s. We expect that once the Catalytic Clothing technology is in widespread use, considerable reductions in the levels of the pollutants will be observed using those monitors. Anecdotal evidence also says that people notice that it’s easier breathe when photocatalytic products are used.
19. Is it measurable?
Yes (see above)
20. How has the technology been applied to the first generation products: Herself, and Field of Jeans?
The TiO2 was sprayed on to the garments.
21. What is the Herself dress made of? What are the blue parts – they look like paint?
The fabric of the dress is coated with titania loaded cement and the blue colour is dye.
22. What pollutants can the chemical absorb?
Nothing is absorbed but the photocatalyst causes oxidation of substances adsorbed on the surface. Nitrous oxide is converted to soluble nitrate and volatile organics are converted into fatty acids and soaps.
23. How much air space can they purify? (Or a quantifiable measurement of how much air is purified)
The air (or the dress) have to be moving – if they are moving quickly enough then 1 square meter of coated fabric can take out 0.5 g of NOx per day.
24. Does the Herself dress have catalytic nano particles or is it a photocatalyst? Can we get a clarification on the process, which pollutants break down? Does this mean that the dress only works in daylight?
The nanoparticles on the dress are a photocatalyst. The size of the particles is important. The coating only works in the presence of light and oxygen. It doesn’t need to be sunlight – interior lights work too.
25. Will all pollutants become instantly broken down or will some remain?
Not all pollutants are broken down and some remain.
26. Will there be any build up of Tio2 in the water supply?
Particles that escape the washing machine will enter the waste water system. TiO2 is an inert, white mineral, and only an effective photocatalyst when it is in the form of nanoparticles that can see light. Any escaping particles are most likely in a mass or group already and will definitely form into groups in the water treatment process, aided by its flocculation process. (The flocculation process forms or causes to form substances into small clumps or masses, – a process, which helps to remove “solids”). Some water treatment systems use UV but these are not widespread. Any titania below a couple of mm of water won’t be particularly active because the UV level will be low as will the Oxygen concentration, in other words because it is too dark there will be little catalytic activity. Any TiO2, which enters the waste water system, will be minimal and harmless and will be extracted by the flocculation process as described above.