Episode 5 Wonderstuff

This series is about the stuff we just can't live without.

The cleaners, the cosmetics,

the convenience items that we use every single day.

How do these things actually work?

'I'm Jane Moore and I've set out to discover the hidden science

'in all those household essentials we simply take for granted.

'My journey will put me to the test in the most unusual places...'

Ta-da!

We have made toothpaste!

'..change the way I think about science...'

That is utterly astonishing.

'..and let me see myself in a whole new light.'

Yes, take a product, any product, and chuck away the packaging.

We're not interested in that because this series is about what's inside.

My task is to find out which ingredients do the clever work

and where those ingredients come from.

'Welcome to the extraordinary hidden world of Wonderstuff.'

'So far, I've been on an eye-opening trip

'around some of Britain's most cutting-edge institutions

'that dream up some of those lotions and potions

'that help make our daily domestic lives so much easier.'

But my Wonderstuff tour doesn't end there.

No, the next stop - to stick or not to stick.

That's the new question that's keeping me awake at night.

'So, to help me sleep better, I want to get to the bottom of glue,

'non-stick pans and paint.

'Later in the show, my master of materials,

'Dr Mark Miodownik, will be luring me deep into the unknown.'

It's like Raiders Of The Lost Ark down here.

'Before then, I'm off to get the low-down

'on something that really does hold our lives together.'

I'm on the trail of what makes things stick

and, call me predictable, but to my mind,

there's only one place to start - glue.

Breakages in the home are a real pain,

not helped by the fact that choosing the right glue

is no simple matter.

The choices available seem endless,

but are all these glues really that different

and is there a Wonderstuff that makes one particular type of glue

the daddy of them all?

To find out how glue works,

I'm off to Cambridge to meet Dr Ewen Kellar,

principle project leader at TWI,

who advise everyone from the Ministry of Defence

to Formula One about the right ways to stick stuff together.

But despite all these high-tech applications,

Ewen reckons the simplest way to understand glue

is to start where the ancient Egyptians did -

using milk, with a sticking power we've all seen in action.

Glue made from milk has been around for many thousands of years.

It's called casein. The name comes from the protein -

the actual whiteness in the milk is casein.

'If you fancy trying this at home, use skimmed milk

'and curdle it by adding vinegar.'

I don't know if you can see that, but it's become all rather lumpy.

-It looks like the milk you find in a student's fridge.

-Yeah.

'Ewen then filters the mixture to get just the protein.'

So, what we now want to do is we want to basically

put this back into some sort of solution.

So, this is bicarbonate of soda, baking soda.

'Adding bicarb apparently neutralises the vinegar

'and forces the milk proteins to stick together.'

Little molecules join together, one after the other,

and form very long chains.

'Then, just add water and voila!'

If we leave this now, for a few minutes,

it will settle down into an almost clear liquid

which can then be used as a glue.

This has been used to bond wood.

It was used to bond furniture in Egyptian times.

'You can also get natural glues from wheat, honey and cheese.'

I'm impressed by that.

I never knew you could actually just make glue from the stuff

that you find in your kitchen.

'Apparently, all modern glues use the same principle we've seen here

'called polymerization,

'where molecules form long chains that bind things together.

'So, why are there so many different types of glue?

'Ewen wants to show me how modern glues work best

'when they're tailored to work on specific surfaces

'and he's starting with a wood glue.'

-So, that's the joint of the two bits of wood, yeah?

-Yes.

What we do is we basically put this in the machine

which we see in front of us and we pull it apart.

'A simple wood glue joint can hold together under enormous strain.'

So, we're now at 270 kilos.

That's several of me dangling off the end of this little bit of wood.

Poor thing!

'But try the same wood glue on metal and it's a different matter.'

Here, we've got ten kilograms. The joint is virtually failed.

I'm going to look really strong.

Yay! Look at that!

So, it genuinely is that there are glues that work better

-on a specific surface?

-Definitely.

'OK, but is there a gluey Wonderstuff?

'Something that could bond absolutely anything?

'I'm wondering about what's in those little tubes

'of instant super-strength glue like I use at home.'

And what is this? It's cyanoacrylate.

Yes, cyanoacrylate. It's basically the chemical name of these materials.

So, basically, here, you've got very small molecules

which combine together when you put them in contact with moisture.

They go from being very, very runny

to very, very viscous very, very quickly

and ultimately go hard cos they entangle and lock together.

But it happens incredibly fast - only a few seconds.

Which is what makes it user-friendly because you want it to act fast.

'Cyanoacrylate got its super reputation as a fast-acting adhesive

'on the battlefields of Vietnam.

'To show me how, Ewen's demonstrating with some pork.'

Here's a cut. So, basically, what the doctor would do

would be just literally lightly apply the adhesive

on the outside of the cut.

Imagine in a real situation, this wound may well be bleeding,

so the adhesive's got a bit of a tough job to do.

The cyanoacrylate is good at coagulating the blood

and stopping bleeding.

Then, all you would do - you would hold it together, like this.

So, no stitches, just a straightforward bond.

Much, much quicker, much, much less painful than otherwise.

-That has really worked, hasn't it?

-Yeah.

'And now, medics do this with a sterile version

'on our day-to-day wounds.

'Fast-setting, super-strength cyanoacrylate

'certainly sounds worthy of being a Wonderstuff.

'But Ewen's got something he reckons is even better -

'epoxy resin.'

Cos it's so versatile, you know, you can use it virtually anywhere.

The main thing to note, really, is there are two parts.

You'll want to mix these two parts together.

So, chemically, what is in each tube that causes that reaction?

Right, well, on one side, we've got a hardener.

On the other side, we've got what's called a resin.

So, the resin is like the long polymeric part -

that's like long chains of spaghetti,

which is very, very sticky molecules.

The hardener on the other side has essentially...

Has the ability to join one chain of spaghetti to the other,

like rungs on a ladder to form like a cross-link network.

So it solidifies it in that way.

'Sounds impressive,

'but I'm still siding with my cyanoacrylate superglue.

'So, the only way to decide which one's going to be my Wonderstuff

'is a head-to-head.'

Wow! Now, this is what I call a weight!

'We're putting them to the ultimate strength test-

'to lift a bag of sand weighing nearly a tonne.'

OK. Well, let's give the old super-strength glue a test, then.

'This is the equivalent of sticking a small car to the ceiling

'with a square inch of glue

'and the power of my cyanoacrylate has actually got Ewen worried.'

So, it's taking a load, now.

I don't believe it!

Cor, blimey! Did it come off the ground?

-It did come off the ground...

-Yeah, a little bit.

..for a nano-second.

It's a good job I've got a strong heart, isn't it?

'But can Ewen's poxy little epoxy resin beat that?'

Maestro, lift!

-Judging by the big bang last time, I'm standing well back.

-You're not going to get up close?

No. Too right I'm not.

OK.

It's starting to lift off the floor.

Look at that!

Well lifted off the floor, that is.

So, if you really wanted, we could lift this really high

-and you could stand underneath it, if you wanted.

-Yeah.

Thank you very much. My days in the circus are long over. Thank you.

It's absolutely holding steadfast, though, isn't it?

'I'm not always so gracious in defeat,

'but it's a clear victory for epoxy resin.

'No wonder this glue turns up in high places.'

-Is that an aeroplane wing?

-Yeah.

-You can't glue an aeroplane wing on, can you?

-Yes, you can.

In fact, it's actually starting to happen, now.

Glue's coming back, now, to being used more and more,

especially with more modern materials which...

It's difficult to know how else to join them together.

I mean, even down to the fact that your brake pads are all glued on.

So, you're trusting your life every day, every time you brake, to glue.

Ewen, I'm getting the train home, or are they glued as well?

Quite a lot of them are, yeah.

'In fact, epoxy resin is so reliable,

'we use it in the construction of aircraft, cars,

'boats, golf clubs, skis and snowboards.

'In fact, anywhere where super high-strength bonds are required,

'and epoxy glues can stick wood, metal, glass, stone and plastic.

'A Wonderstuff indeed.

'Ewen said that glue's brilliance lies in it being a polymer,

'but what exactly is a polymer?

'Materials scientist Mark's been raiding his stationery cupboard

'in order to explain what he reckons

'are some of our most marvellous molecules.'

Hello, strange little man on park bench.

-Fancy seeing you here.

-Just having a sit down and a think.

What's all this about?

You've been talking about glue.

There are examples of things called polymers,

which is sort of man's attempt to kind of

recreate the wonderful range of materials that nature can create.

These soft, flexible materials that repel water

and can stick to things or not stick to them.

All of that kind of thing that we see in nature all around us.

'Silk, starch, cotton, asbestos and DNA are natural polymers,

'all built from chains of carbon-containing molecules,

'known as monomers.'

Add the monomers together to make these different length molecules.

'Joining together and repeating these same molecules

'is what creates a polymer.'

So, a polymer isn't a chemical, as such.

-It's a sort of... A molecular structure.

-Yes.

Polymer is a category of material in the same way that metals are.

'But why is making chains of molecules so useful?'

By varying the length of the chain, how many units you put together,

you can make something become harder and harder. That's cool.

'Just like I saw in glue.

'Mark tells me that the behaviour of polymers

'is crucial in explaining the science

'of something that does the exact opposite of sticking -

'non-stick.

'In the kitchen, I'd be hard pushed to think of an invention

'that's more useful than non-stick.

'I have no idea what's on my pans,

'so it means my sausages stay unstuck.

'So I'm off to try and find out what sort of wonder material

'could have such a spotless reputation.

'To show me, know-it-all Mark has dragged me down the hill

'to the Millennium Dome?!'

-What are we doing here?

-We're at one of the most amazing buildings in London.

Look at this. Magnificent, isn't it?

Well, yes, it's a magnificent structure,

-but what's that got to do with why we're here?

-PTFE in that roof.

Look, this is the stuff. Again.

Blimey! I thought that would be like a ping-pong ball

-and it's really heavy.

-Heavier than you think.

Yeah, it's really tough, isn't it?

'It turns out that PTFE is a fancy kind of plastic.

'Another one of those clever polymers, by the way,

'and because it has an extraordinary trick up its sleeve,

'it can be found on both the roof of the Millennium Dome

'and inside my frying pan.'

It's the slipperiest material in the world.

Nothing sticks to this stuff.

Even geckos, which can climb up anything at all,

cannot climb up PTFE.

It's so slippery that all the dust slides off it.

-And the bird poo?

-And the bird poo, yes.

-Handily.

-So, it's 600,000 square feet of PTFE.

-Wow!

That's a lot of frying pans.

-It is. How many frying pans is that? Let's calculate it.

-Let's not.

-OK.

'We rely on PTFE's super slipperiness

'for all sorts of other essential jobs, too.'

Famously, the astronauts who walked on the moon

had PTFE coated inside their space suits

because when they're moving about in space,

they can't have friction on the inside

which might cause a little hole to form cos then, they would die.

It's starting to be used inside the body.

So, like an artificial hip.

Cos it's going inside,

you've got the friction constantly of the socket and the joint.

Coated with PTFE.

It's inert. That's the other great thing -

it doesn't react with anything.

So you can put it in the body and it's going to be fine.

'I'm chuffed to have discovered that the coating on my frying pan

'is the world's most slippery plastic,

'Mark isn't satisfied.

'He reckons the true Wonderstuff in this story

'and the key to why it works,

'is not the non-stick polymer itself,

'but a remarkable natural ingredient in PTFE.

'He wants to get to the bottom of it, literally,

'in this mine in Derbyshire.

'Here we go.'

Have I mentioned that I'm claustrophobic?

It does involve a bit of down. I have to admit that.

'The Blue John crystal mine goes down 245 steps.'

We're going right underneath the Pennines, Jane.

Down, down, down.

This had so better be worth it.

It's like Raiders Of The Lost Ark down here.

Or Raiders Of The Lost Mark, hopefully, in a minute!

'But what on earth is all the way down here

'that could be my Wonderstuff?'

I've brought you here to see a very special piece of rock.

It's all around us. This is a mineral fluorspar.

It has in it this element fluorine

and we react fluorine with the ingredients of polyethene

and we get this amazing other plastic,

which revolutionises your life.

'I still don't get how the fluorine you extract from these rocks

'makes PTFE such a super slippery plastic.'

-I've got some here, actually.

-Oh, it's a gas.

It's a green gas and it's incredibly reactive.

It's so reactive we had to put it into two containers,

and even then, it's trying to get out.

This stuff will react with almost anything.

So, you never find it on its own

because anything it comes across, it just forms a compound with.

'I'm sure I want something that reactive

'coming into contact with my food.

'But Mark tells me that it's this super reactivity

'and the strength of the attraction between the fluorine

'and other elements in PTFE

'that are the secret to its slippery success.'

The fluorine bonds in the PTFE -

they are so uninterested in bonding to anything else

that they make it non-stick.

All they're doing is handing over the energy, the heat,

and they're not laying claim to anything else.

'So it was worth sticking with Mark all along.

'Scratching the surface of non-stick frying pans

'revealed the true Wonderstuff to be fluorine gas.

'Fluorine is a dangerously powerful oxidiser

'and so reactive it only exists in its pure form out in space.

'Here on Earth,

'its ability to react with a wide range of other substances

'make it extremely useful.

'Plus, it's gentle enough to be added to toothpaste

'to keep our tooth enamel strong.

'So, I've discovered some of the stickiest

'and the slipperiest substances on the planet,

'but I'm still stuck on one other question.'

What's the stuff that every home is literally covered in?

In fact, it's probably staring you in the face right now.

'I'm talking about household paint.

'How can it be runny enough for us to roll on,

'yet still sticky enough to stay on the wall?

'So if I'm searching for the Wonderstuff in paint,

'surely that means a nice trip to the Sistine Chapel?'

Some reporters get to cover the Oscars,

others get to go down the Amazon.

I get to come to a paint factory in Slough.

'And that's because Slough is home to AkzoNobel,

'who discovered that famous polymer so crucial in PTFE -

'polyethene.

'They also make a lot of paint.

'Richard Barcock is their UK Paint Technical Manager

'For Decorative Coatings, no less.'

So, Richard, in general terms, what is paint exactly?

Paint is a coloured powder in a liquid glue-like medium,

which you can easily apply to surfaces in your home.

'Richard breaks down exactly what's in a basic paint for me.

'There's water,

-'something to make it opaque...'

-Which gives you this good covering.

-'..thickener...'

-To increase viscosity of the paint.

'..a surfactant and an anti-foaming agent...'

To keep that level of bubbles down.

'..and then, there's a binder, which I'm told is basically,

'yes, you've guessed it - glue.

'The boffins here test different gluey binders to destruction.

'They're stretched, scuffed and exposed to the elements

'to find the binder best suited for any surface

'you might choose to paint.

'And they've perfected another clever property in their paint as -

'watch out, here comes another fancy title -

'Physical Characterisation Team Leader,

'Dr Tom Kerwin explains.'

One of the tests that we do here

to get a feel for the consistency of the paint

is actually just try and cut a cube from it.

You'll see that,

-we can cut this cube out.

-Look at that!

A slice of paint.

'So, in the tub, it's solid,

'but stir it up and it goes all liquidy.'

Can I have a go? I like a bit of mixing.

Yeah, have a go.

Give it a mix and then have a go at cutting another cube.

Look at that. Trying to cut a cube out of the paint.

That is fantastic.

That, now, would go on a wall very nicely indeed.

'It's now miraculously lost its stickiness

'and is much easier to apply to the walls.'

It has this key property known as shear-thinning.

That means that the viscosity,

the resistance of the paint to flowing,

decreases the harder you try and push it.

And when you stop sort of, applying a force to it,

does it then solidify again?

Exactly. That structure we built with the thickeners

comes back and stops it slipping back off the wall.

'So the clever paint polymer goes sticky again

'and dries hard and fast to the wall.'

-Clever!

-Indeed.

-Yeah, fantastic.

'Seeing how much science goes into a pot of household paint

'has made me come over a bit EMULSION-al!

'But hold on. Even though I now understand how it sticks to my wall,

'aren't we forgetting the most obvious thing about paint -

'its colour?'

For example, Bongo Jazz, anyone?

It's orange, apparently.

We buy 300 million litres a year of this stuff.

'We can now get hold of just about any shade under the sun.

'So is there any hidden genius I need to know

'about what gives paint its colour?

'I've agreed to a rendezvous in a secret location outside Oxford

'with architectural colour consultant Patrick Baty...'

A yellow ochre pigment in this country.

'..and avid pigment expert Keith Edwards.

'His speciality - digging colours right out of the ground.'

Hi, Keith.

To my untrained eye, I'd think that was sand.

Well, it is partly sand,

but mostly, it's very pure ochre pigment.

It was used by famous artists such as Constable, Turner,

from probably the 17th century up until the early 20th century.

So special stuff?

Very special stuff.

It feels like cumin or something like that.

It is very like it, yes.

'Apparently, natural paint pigments like this

'have been used for over 30,000 years.

'Keith's spent most of his lifetime in pursuit of perfection.'

We've got some lovely colours. What's this purple one?

It's murex purple - it's the most expensive pigment ever produced.

-Its present value is about £50,000 a single ounce.

-Goodness me!

-So where does it come from?

-It comes from the murex shellfish -

a sea snail from the Mediterranean.

'Keith's commitment to colours is astonishing.'

Keith, can I just ask you, what colour is your living room?

That's a hard one.

-Don't say magnolia!

-Yes, actually, it is.

'But in my hunt for what gives paint its colour,

'he's got a bit of a shocking revelation.'

These, really, are only stains.

That's the basis of modern paint.

We can't do without titanium dioxide.

It's the purest white we have, really.

Yes. It is the purest, most opaque white we have.

Paint without titanium dioxide

would be like making a sandwich without bread.

'But why is this white pigment so special?

'Apparently, it's because titanium dioxide

'makes such a dense and bright colour.

'Back in London at Patrick's shop, I learn that titanium dioxide

'is now in pretty much every pot of paint we buy,

'whatever the colour.

'And Patrick owns a unique piece of history -

'a tiny chip of paint that shows why titanium white became so invaluable.'

What we've got here are 71 individual schemes of paint.

These were applied to the outside of a building

that we know was built in 1705.

What we've got there is the full history of the house,

which takes us right the way through

things like the discovery of Australia.

History encapsulated in a little chip of paint.

A little chip of paint.

'Patrick's had a photograph made so we can see what's happening up close.

'It turns out the old base for paint was downright dangerous.'

From 1705 to about 1939, here,

all of these are based on lead carbonate.

-That is the main constituent of these paints.

-Poison?

-Indeed.

-Highly toxic.

-Good grief!

So, we've got lead carbonate through to the Second World War.

We then have a couple of schemes based on zinc oxide.

We've got the introduction of brilliant white.

You can see this much brighter sequence of coats,

which is about 1960, 1962.

-So, that's when they started to use the words brilliant white...

-Absolutely.

It was quite impossible to achieve a colour like that,

a bright white, in these earlier days.

'And all that's down to good old titanium dioxide.'

It's non-toxic. It's readily available. It's not too expensive.

Most importantly for a paint, it covers very well indeed.

A couple of coats, that's all you need.

-So, it revolutionised the paint industry?

-Completely.

'With cheap, safe titanium dioxide in your paint,

'all you need is a couple of coats to get good coverage

'and rich colour.

'But exactly how is this extraordinary ingredient

'achieving this? Back to Mark.'

I've got a sample of wallpaper,

which you may or may not want to get rid of.

It's all the rage now again, you know, florals.

-We'll have an argument about this.

-I don't think I'd have it on my wall.

We want to get rid of it with some white paint.

'Time for the ultimate paint challenge.

'Mark has mixed up some titanium dioxide and plain water

'to see how well it covers up the horrors of his floral wallpaper.

'After just one coat, the results are striking.'

These titanium particles are little crystals.

The light's coming in,

and it's only getting through a small part of the crystal

before it gets pinged out again

because it's got a very high refractive index.

'That means it's like thousands of tiny mirrors

'bouncing the light back out, and that's not all.'

It does some other weird things, too. It makes surfaces self-clean.

It's photocatalytic. So, when light hits it,

if there's any organic matter near it,

it makes it disintegrate.

That sound astonishingly clever.

'When sunlight hits a titanium dioxide coating,

'any dirt rapidly oxidises and can then be washed off by the rain.'

-TD, let's hear it for TD.

-I totally agree with you.

We use four million tonnes

of this naturally occurring mineral every year

as a base for paint of any colour.

Its ability to give excellent coverage

means it also turns up in cosmetics and sun creams.

Pretty much everything that's white in your house

contains titanium dioxide.

Your white goods, your writing paper.

It's even in your food as E number 171.

Cottage cheese with added microscopic mirrors, anyone?

For me, the search for the Wonderstuff

behind why things stick or don't stick

has really brought it home how we rely on clever chemistry

every single day without even realising it.

The chance discovery of the world's most reactive element, fluorine,

led to the chance discovery

of one of the world's most slippery substances, PTFE

which in turn, led to the culinary revolution,

enabled by the non-stick pan.

So who would've thought there was such a fascinating history

behind an everyday object we all take for granted?

'Next time, I get under the skin of preening products...'

Ow!

'..in my search for the magical mist-grabber in moisturiser.'

I'm absolutely amazed that just a clear liquid

can do this amazing thing.

'Mark tries to explain how anti-perspirant

'prevents pungent pongs.'

What if too much comes out? Then you feel uncomfortable.

I wouldn't like to meet a man who sweated quite that much.

'And on the hunt for the Wonderstuff in sunscreen,

'I stoically endure utter humiliation,

'all in the name of science.'

Oh! Oh! Oh, God!

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