Nanotechnology at home

Katie King went around her home before work with the help of material scientist, Lauren McHugh from the University of Cambridge, to show that nanotech is very commonplace and answer Sally Le Page's questions...

Sally - What is nanotechnology other than yet another buzzword?

Katie - Oh, but it is my favorite buzzword. Well, for starters, 'nano' means very, very small.

Sally - Okay. But how small is small?

Katie - Well, much smaller than those iPod nanos that you might remember. What we're talking about is a millionth of a millimeter. Stuff on the near atomic scale. Nanotechnology is about controlling and building materials on this length scale for a whole load of different purposes.

Sally - Why do you need to control it on such a small scale? Surely if it's so small, it won't make much of a difference.

Katie - That is a good question. As an example, let's take diamond and graphite. Both of them are made up of only carbon yet they have very properties. I can't imagine you'd be best pleased with a ring, with a chunk of graphite on it.

Sally - I dunno. I mean, I'd never be lost for a pencil.

Katie - That's true. These differences are down to their nanostructures and their differences in their nanostructures. By controlling things on the nanoscale, we can end up with some very different and very interesting properties.

Sally -
But when exactly am I gonna need a nano material? This all sounds like stuff from a science fiction novel and not something particularly useful in my everyday life. We've all got bigger problems to worry about right now.

Katie - I thought you would need some convincing so earlier this week I went around my home before work to show you that nanotech is very commonplace.

Katie - Right time to get up. It's a beautiful chilly day outside. First thing's first time to take my lateral flow test. They always made me want to sneeze. We are all more than familiar with lateral flow tests, but did you know that the red lines are in fact made up of gold nanoparticles? We all know gold is shiny and yellow, but when we cut it up into tiny nanoscale chunks, it takes on new properties and appears red. Nanoparticles of materials can have very different properties compared to the material at larger scales, which is one of the things that makes them so useful. While I wait for my test results, time to shove a wash on. You may not know this, but powdered washing detergent contains a nanomaterial that makes our detergents more efficient. Lauren McHugh, from the University of Cambridge is going to tell us a little bit more.

Lauren - If you look on the back of a box of soap powder, you'll probably see zeolite as an ingredient. Zeolites are crystalline materials and they're composed of aluminium, oxygen and silicon. They contain microscopic channels, which we refer to as 'pores'. The cage light structures of these zeolites make them really useful in water softening. In water softeners hard water, such as that we have in Cambridge, contains calcium and magnesium ions, and it's passed through sodium containing zeolites. The calcium and magnesium ions in the water are trapped by the zeolite and the sodium ions present in the channels of the zeolites are released. The new water contains sodium ions, and this can be considered 'soft'. When washing and hard water, magnesium and calcium precipitate with soap, which hinders the formation of subs. However, when the ion exchange occurs, the sodium ions now present in the water do not precipitate with the silk and this leads to the formation of more suds and a more efficient detergent.

Katie - I guess that's one way of saying we are slightly less bubbly here in Cambridgeshire. All of that hard water and minerals in the water can mean that tap water can leave that off-putting taste for some people. Bet you didn't know that another place where nanotechnology is used is in water purification filters. Lauren, what's going on inside these filters?

Lauren - Water filter will contain activated charcoal. This is another highly porous material similar to zeolites. Activated charcoal has an extremely high surface area, and it's really effective in absorbing contaminants. The chemicals that activate charcoal tends to remove would be things like chlorine or anything that has an odour and then these water filters will also contain ion exchange resins. These will help to again, remove some of the hardness from water.

Katie - While that filters, I better go brush my teeth. My toothpaste also contains activated charcoal. What's that meant to do for my teeth?

Lauren - In cosmetics a lot of the time activated charcoal will be used to detoxify. If you go into any pharmacy, I'm sure you'll see an abundance of face masks that say 'these activated charcoal face masks will detoxify your skin and remove impurities.' Similarly, if you then take an activated charcoal toothpaste it will claim to remove stains from your teeth. You're going to be binding impurities to surface the carbon.

Katie - Do you think it works?

Lauren - I do have my reservations about it. Activated charcoals are actually very granular. I think a lot of the time you're probably just rubbing a part of the surface if your teeth off by using these toothpastes. So it's up to you, they may do something about removing stains from your teeth, but you're also probably rubbing part of your teeth off in the process. So very much up to you whether you use them or not.

Katie - Right now that I've, nanoteched my teeth, my COVID test has come back as negative. I'm running late. I need to get out the door and get on my bike with a frame that's reinforced with, you'll never guess it, carbon nanotubes. So you see Sally nanotech really is everywhere.