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Professor Tony Ryan
[Shot of Sheena.] So we can see how to make nylon, by the nylon rope trick and we can see how to make a rope by twizzling it all together, but this spider would drop from its own rope and it gets everything it needs from eating wasps and flies and other things that go into the web.
[Shot on screen of wasp trapped in web.] And the wasp contains all of the elements that she needs to spin her web.
So inside this spider and this spider - and this spider, in that belly is enough silk to make four hundred metres of her web. [Shot of spider in glass container.] That's a fantastic length from something so small.
So, I want to give you a feel for what four hundred metres looks like. So there are four of these that are being passed round [shot of children passing round spools of line] , each, and keep, you need to pass 'em quickly, just so you can feel how quick, how much silk is stored inside this tiny little spider.
So what about its fantastic web?
When she goes to make the web and actually this is, this one's Fred, I think, in here.
He puts special dabs of glue down and that glue is made from the same silk that the strong fibres in the web's made from. [Shot of spider in glass case.]
So a little dab of glue goes down with no pulling on the thread and then to make these load-bearing sections, the thread gets stretched and then to make the circular bits of the web, which you can see up on the screen, the spider does something completely different.
He makes soft fibres - and those soft fibres are coated in something that absorbs water.
So let's say I'm a wasp and I'm running towards a hard web and I run across, boing, bounce off and I'm not going to get eaten - that's no good for the spider, because as well as being the home, this web also has to be a source of food.
So these fibres stretch slowly and absorb the energy and so the wasp gets wrapped up and this clever little spider extracts all the elements she needs to make that ever important silk.
So this whole construction, load bearing, reminds us of something that human engineers do.
They need far more than the four hundred metres of web that are out with you now. Took you an enormous long time to pass that out.
[Suspension bridge model is wheeled on.] Now this suspension bridge has all the same features.
It has load bearing cables and they're anchored. [Shot of cables.]
Remember, the spider anchors by putting a little dab of glue down. Human beings have to drill holes and put big bolts in.
[Tony points out cables.] These fibres also bear some strain - these are nice and flexible, so if the bridge rocks or moves in the wind, it can take the strain, just like the soft fibres that we saw in the spider's web.
[Shot of Golden Gate Bridge on overhead screen.] Now, there's the Golden Gate Bridge up there and we've even started to make bridges from plastics, just like we have the construction from the spider, of this fantastic polymer.
So you've seen all the evidence now, it's time to get your voting cards out. [Audience reach for voting cards.]
So who's the best engineer? Red for the spider, green for the human? Well it's not quite unanimous, but there's far more red than there is green. It's a bit like being at a Man United game and me being a lad from Leeds - that's not such a good thing!
So the spider wins and just before we leave for the break, I want to give you a word of warning.
[Overhead screen shows black-and-white archive film footage of suspension bridge collapsing.] Sometimes, human engineers can get it wrong.
We draw inspiration from nature, but we often break our design rules and this can mean disaster.
The engineers that built this suspension bridge got their sums slightly wrong. They should have taken a leaf out of Sheena's design book.
Remember if we're going to use nature, we have to obey the rules. [Applause]
Professor Tony Ryan
[Tony & assistant bring in sheep.] Throughout history we've relied on nature's polymers for our survival.
We've kept flocks of sheep for thousands of years and used the wool they produce to keep us warm, but the polymers we use aren't just from animals.
They are found in the plant kingdom too.
Cotton is farmed for its polymer and cellulose can be spun into fine threads that can be used to make everything from cinematic film to fancy undies.
About a hundred years ago just about everything we wore was made of these two natural polymers. [Shot of sheep.] But how does this compare to today? How much ... [Laughter] ... uncooperative sheep's wool do you think you're wearing? Right?
[Tony looks at clothing worn by members of audience.] These guys have synthetic fibres, nylon. They also have cotton and I'm looking round - this young lady here, stand up, give us a twirl, yeah? There's some lycra, some elastane in that top that makes it nice and stretchy.
And over here, this lovely shirt - let me just have a feel.
That's made from polyester.
[Boys wearing grey school jumpers.] And then these two boys down here, they have the classic school itchy jumper. [Laughter]. Right. And they're made from an acrylic polymer. And that polymer is kind of a throwback to the first synthetic fibres and they were made by wet spinning.
And I'm going to show you how wet spinning works now.
So Annie's bringing on a polymer solution and a big tray full of water. [Table with polymer solution in container is wheeled in.]
[Tony holds up solution.] Now we're going to make the fibre by taking the solution and you can see it is a solution - it's a liquid and we're going to extrude that liquid under water and the solvents exchange and the polymer doesn't like the water, so it precipitates and becomes a solid. [Shot showing process.]
I can even pick these fibres up.
They've made something that looks like the cloth you might use to clean up in the kitchen. Thank you very much.footage in room outside lecture hall/Tony stands by machine
[Footage on overhead screen of spinning factory.] But we don't make that many synthetic fibres these days by wet spinning.
Nowadays we use melt spinning and that relies on pumping a polymer through a hole, very much like the hole in the spider's bum to make a solid line and then we can use that solid polymer to do all our weaving processes.
How do we know what the structure of the fibre is?
Well outside of here, because the model was just too big to bring in to, to show you, we have an X-ray machine and I'm going to show you the X-ray machine. [Footage in room outside lecture hall/Tony stands by machine.]
[Tony demonstrates process of machine.] So here is an extruder - that's this thing up here.
And we've put the polymer chips in and the polymer chips go down a hot tube and the molten polymer comes through the spinneret.
Just think of this as being the spider's bum.
And then we take the polymer down in a line and then the synchrotron, which is a massive machine, about the size of a football field, produces X-rays and the X-rays come through, interact with the polymer fibre and are scattered and rather than showing you the detectors, what we've done is we've played back what those detectors see on these TV screens.
So this TV screen shows you what the detector sees, about the size and shape of the crystals.
And this TV screen tells you where all the atoms are, so we can get the crystal structure.
And eventually we can build a model like this one, of the polymers rattling around, to become crystals.
[Tony walks back into lecture theatre.] So I'm going to go back in now, because you don't have to use X-Rays to get crystal structures, to see crystallisation.
So when we look under the microscope - I'm just going to fiddle with the temperature.
So there's the crystal structure of the nylon and now, oh look, my polymer's about to crystallise and you can see up on the screen, the crystal growing through the molten polymer.
That's what happens when we do the extrusion process to make fibres. We can tell where all the atoms are going. [Process is shown on overhead screen.]
So it's finished crystallising.
[CU shot of molecules on screen.] So what happened to the molecules during that? Well they started to rattle around and all the long chains rattle so that they start to fold up.
And there it's kind of jerky, because this is a real-time computer simulation of what happens to a single polymer molecule whilst those crystals are growing. And you can see they all fold up.
So we've learned a fantastic amount about crystallisation. In fact, this is a subject I do research on and today I rang up my research group. [Overhead screen shows film footage of Tony's group.] And they're out in Grenoble, working on another synchrotron. And they were really excited, not because I was giving the Christmas Lectures - because they actually made a discovery today, about how crystals start, so Ellen's giving it the big thumbs up, because that's the best scientific result she's had in a long time and the guy you can hardly see in the middle is one of my best mates, Wim Bras.
And we worked together on this synchrotron to try and understand what the molecules are doing, all the time they're being processed.
So, we've learned a lot about how these fantastic molecules crystallise.
But all the polymers are intrinsically colourless.
But if we look around today in the audience, you're all wearing bright colours, fantastic colours.
Even the school uniforms have interesting colours, right. When kids went to school in the 1850s, they didn't have all these bright colours.
It wasn't until William Perkins, who was an organic chemist, invented mauve, the dye, that we got a range of bright colours.
Prior to that only rich people could wear bright colours, because to make the dyes you had to crush up beetles, or find a tree that exuded sap that was exactly the right colour.
But now, everyone can have colour.
And there was an explosion of this. [Tony holds up mauve 't' shirt.] This mauve colour was the thing to be seen in, in the 1850s. Everyone wore it because it was the only colour available! [Laughter]
[Tony holds up velvet top.] Now they wanted me to do the lecture in this, I don't know whether I quite approve.
But these kinds of garments that are brightly coloured have only been available because we can develop molecules that have specific colours and we can make them stick to the fibres we want.
[Table is wheeled on.] Now we've had some volunteers already to help us with this dyeing experiment.
[Flag is held up.] Now, a couple of weeks ago, my mum made a flag and we can see the flag, it's white, right?
And here we have a murky liquid.
So we're going to put the flag into the murky liquid.
[Annie puts flag into glass container.] Annie has to do this because it's hot and we, we can scald her, we don't want to scald the volunteers, right, it's about seventy degrees.
And she's going to pull it out and our volunteers will rinse it - there's nothing dangerous about this at all.
So you need to give it a good dab, squidge it around and then when you hold it up, which you can do now, hold it up the right way around and ... [hums 'Land of Hope and Glory] ... [Children hold up flag with Union Jack colours.]
[Applause.]
Right, we made this flag just by dipping different fibres into a bath that contained different dyes.
And the blue fibres stuck to where the blue fibres, the blue dye stuck to where the blue dye was supposed to go and the red dye stuck to where the red dye was supposed to go and the white was completely unaffected.
[Tony holds up different coloured rugs.] Now this process of making something that's white and then colouring it afterwards, actually helps in industry.
Because you can just run your carpet-making factory, making white carpet and then, let's say that blue and red carpets are the current fashion and everyone wants blue and red, you can dye them afterwards using exactly the same technique.
So this carpet, which has three shades of one colour and two shades of another, has fibres that are specially modified on their surface to interact with those dyes that give you blue and red.
So they take those up and they leave the others behind.
Now, carpets are great, but they're on the floor, right, and what happens to them?
[Tony empties contents of vacuum cleaner on to carpet.] Well, they get covered - all this stuff get sucked out.
So if we grind it in, right - [laughter] - you can see what happens.
[Speeded-up shots of people walking over carpet.] Now when you guys came into the lecture theatre, you came through a doorway and a month ago we put a carpet down in the door.
And the carpet was originally this colour and as it got walked over - then out came this writing. [Tony holds up section of carpet with writing on.]
How did that happen?
Muddy feet go over it, it's yellow to start with and all of a sudden yellow writing comes out of a dirty background.
In actual fact there's as much dirt in the clean part as there is in the dirty part.
And all the mums and dads upstairs are wondering where they can get a carpet - [laughter] - like the clean part.
Well what happens is, these fibres are round, like this one at the bottom and the round fibre acts like a magnifying glass.
[Shot of perspex model showing word 'sporco'.] Are there Spanish speakers in the house?
And what does 'sporco' mean?
It means 'dirt' - right, so you can see the dirt through the lens.
And so the carpet manufacturers thought, well if we can make the fibres scatter the light, you won't be able to see the dirt that's behind.
So they put something in that made the image of the dirt become a little more blurred.
But that didn't help with the long-life properties of the carpet.
So then they developed a fibre that rather than being round was like a 'y' shape and if I can just, there, you can see you get multiple images of the dirt from this, so the light's being scattered and you actually see more of the fibre than you do of the dirt.
But the solution to the problem which is now you can hardly see the dirt at all, right, there's no 'sporco' to be seen.
And in here the fibres have holes running down the middle.
So this fibre isn't a fibre at all - it's a series of tubes of air and those tubes of air scatter the light.
[Tony reels out roll of bin liners.] So we've seen how there are lots of fibres that are made from polymers, but the majority of polymer gets used to make film and we see it everywhere.
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