Summary:
As you watch the video, listen to what Rachel has to say about:
Captions:
Dr Rachel Caruso: Welcome. It’s quite an opportunity for me to be able to speak to a large group of young and enthusiastic
women who are interested in the sciences and today I ‘m going to be talking about chemistry.
In particular Materials Chemistry and how it can shape our future.
So, a little bit about myself. I’m working at the University of Melbourne in the School of Chemistry.
I went through the school system in Melbourne.
So, I went through primary and high school there and then I went to the University of Melbourne to study.
And I was at the University of Melbourne where I found that chemistry was what really interested me.
I saw there were many applications to chemistry and that chemistry could have a big impact on the future
so this was something that really excited me and made me want to study the chemistry.
After I had finished all my studies at the University of Melbourne I went across to Germany
and I worked in Germany for a number of years in different research institutes and just furthered my career
in that way so that I learnt to do extra things apart from what I’d learnt during my studies.
And then I moved on and became what is called as a group leader.
I looked after a group of research students and people interested in doing research
and we started building up research expertise.
Summary:
Listen to Rachel describe the following elements of her research:
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Today what I would like to talk to you about is how does chemistry work and what is material’s chemistry in particular.
Now you’re probably all very familiar with research laboratories
within your own schools you’ll have your research labs or your schools where you do your experiments.
And you have basically bench tops and perhaps fume cupboards where you do experiments in the laboratories.
As you continue through your career you still have these but then you add extra things to it.
And so some of the equipment I work with a lot are large pieces of equipment.
And this particular example that I’m showing here is an electron microscope.
The electron microscope works in a very similar fashion to a light microscope
where you’re using instead of light an electron beam.
That electron beam goes through your sample and you can see your sample on the nanometre scale okay?
So you put your sample into the transmission electron microscope and you can increase that magnification
so that it’s a really high magnification; you can see in effect that atoms that are making up your sample.
Summary:
As you watch the video, listen to what Rachel has to say about:
Captions:
As a materials chemist, not only do you make materials, not only do you characterise
or look at your materials, you’re also looking at how does it function in an application?
So another thing that a lot of us are doing:
we take our samples and we put it into a certain application to determine how well our sample works.
The example that is shown here:
a young lady is looking at how her material works as a fuel cell electrode.
So, she’s putting her materials in, she’s testing how efficient and how effective her material
is in fuel cell applications.
I want to start with a couple of examples as to why materials in particular are very important.
So, as we see here we’ve got a spider with a large spider web
and as scientists and engineers we study the spider silk.
Why is it that a spider’s silk can be so flexible and yet so strong?
It’s the strongest fibre that we know.
It’s stronger than steel on a weight for weight basis. It’s really flexible.
Flies fly into the web and there is give.
It just doesn’t just stay still, there’s give. It’s a flexible material it’s also bio degradable.
So, how can we learn from the spider – from nature to make materials that have the same sort of properties?
So, a group of people, a chemist in the USA. He has actually studied the composition of a spider silk
and what he finds is there are areas which are very crystalline,
so ordered areas and then there are other areas which don’t have order.
It’s an amorphous area, okay.
And as you put strain onto this part of the web the areas that are crystalline line up so they align
and the areas that weren’t ordered allow that flexibility in the actual web.
And so scientists have looked at this and tried to copy this.
They take carbon nanotubes and another polymer.
The carbon nanotubes are very ordered in their structure they take the polymer,
they mix these together and basically spin a fibre and this fibre has very similar properties to a spider silk.
It’s very flexible, the addition of the actual carbon nanotubes means that the fibre can conduct electricity
and can also be used as a thermal heating device.
Here’s a picture which shows the fibres incorporated into a cloth material.
And you can think of many different applications where you could use these sorts of fibres
to keep yourself warm just by simply turning a switch okay.
You could use these to power a GPS system so you know where you are globally positioned
and the Defence Force obviously find this really interesting.
If you could actually wear your global positioning system rather than having to carry the device with you.
So there are many, many applications
where we could actually use conducting fibres that have high, high strength.
If you have enough of the fibres in this material it’s also a bullet proof cloth okay?
So, bullets cannot penetrate,
it is that strong it can prevent the penetration of bullets through.
Summary:
Listen to Rachel describe the materials she works with:
Captions:
Dr Rachel Caruso: If you have a waterproof material what sort of feel do you expect from a waterproof material?
Student: Oily.
Dr Rachel Caruso: Oily. Yes, very often oily.
Student: Rubbery.
Dr Rachel Caruso: A rubbery, very much a plasticy rubbery type of feel or oily. Okay
Scientists have been working on this and have produced a fabric that just feels the same as any other fabric.
What they’ve done again is taken very small carbon molecules,
short molecules with carbons in them and basically they’ve put these onto the fibres of the cotton or the wool.
They heat the system and that causes them to bind.
So there’s a strong bonding between the actual cotton or the wool fibres.
And it works, in effect like the peach skin has the little hairs on it and it’s very hard to wet this surface.
So the little hairs on the actual fibres hold the air in and prevent water from actually penetrating
and getting in close to the fabric
very soft fabric so you do not have to change the actual feel or composition of the material to a large degree,
you’ve just put these little fibres onto the initial wool or the cotton.
Summary:
As you watch the video, listen to what Rachel has to say about:
Captions:
Another lot of work that has been done is actually changing the optical properties of a fibre,
so a group of researchers has been looking at glass and polymer composite fibres,
so here we’ve got glass and polymer,
so a core shell material, and you can actually change the thickness of this fibre
just by altering the actual conductivity through the fibre,
you can change the thickness and this changes the actual optical properties, so it changes colour.
This is currently being used in art form okay. You take the fabric, you have these fibres in the fabric,
and you can the change the colour simply by turning a switch and putting electric current through the actual fibres.
And so you can imagine, you’ve just finished a day at work, you want to go out,
you don’t want to actually change what you’re wearing
and so you go through and with just a simple click of a button you can change the colour of your clothes.
You go to a party somebody else is wearing the same dress as you.
Flick a switch you’ve got a different coloured dress to the other person. So a very simple,
but effective means to be able to change what it is you’re actually wearing.
People in Italy are also very interested in looking at fibres that glow. And so they’re looking at luminous fibres
and they’ve got a lot of interest in this in the bridal area.
So a lot of brides wanting to make a real fashion statement get a dress that when the lights go dim they glow.
Okay. Their dress is white it glows and you can imagine other applications.
If you had a handbag; you’ve been out at a party all night, it’s dark you get home you open your bag it glows
from the inside you can very easily find your keys or whatever you need to get inside.
And so there are lots of applications where just changing the properties of a fabric you can use
and have very interesting properties in the materials.
Summary:
As you watch the video, consider the following questions:
Captions:
Another example that I like a lot is the lizard, okay we have all seen lizards,
and we’re all quite astounded by the fact that a lizard can walk up a wall and walk across a ceiling.
It sticks to things okay?
And so the fascination is: how does the foot or the paw of a lizard function?
How does it work? It’s very interesting.
If we actually have a look at the paw or the foot of a lizard.
Okay here we see it has its feet
and if you have a look up really close to the actual foot you see there are very small stalks?
Now these stalks are finer than your hair. So the diameter of them is finer than your own hair.
There are over five hundred thousand of these on the foot okay?
Looking at the stalk further you see there are a lot of split ends on the end. Okay?
And it’s these split ends which are shown here they're called spatula.
These split ends are what come in contact with the surface that the lizard is actually walking on.
So it doesn’t matter whether the surface is wet or dry.
It doesn’t matter what the properties of the surface are if these little spatula come in contact
with the surface they're set, certain interactions. They are called Van der Waals interactions.
That occur between the surface and these little spatula that make the lizard stick.
Now a lizard can hold, they say, up to four hundred times its own body mass okay without unsticking.
So as humans we look at this and think that’s pretty amazing
what can we do to make a material that does something similar to that?
So scientists in the U.K have been working on a similar type of material.
Here it’s a polymer and what they’ve done is they’ve etched away so they’ve removed areas of the polymer
so that they’re left with these small areas of polymer with a similar sort of spatula top,
on the top of these little fibres.
And they’ve been able to make this sticky tape which allows them to stick things onto surfaces.
If you think about a lizard, a lizard can use its foot many, many, many times.
It doesn’t use its foot five or six times then it’s no longer sticky. Yeah?
It keeps using its foot over and over again.
With this, scientists in the U.K have been able to make up a sticky tape using a one centimetre square
so about this size of sticky tape. They’ve been able to stick three kilograms to that sticky tape. Okay?
The example they used was a toy Spiderman and so they could stick the toy Spiderman
to the glass surface they could unstick him
and then stick him back up again about five times before the sticking power was reduced significantly.
And so we look at nature and we see what nature can do and we try to copy what nature has done.