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Surface chemistry -

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Erica Wanless: We usually take a dry, pristine surface, like some mica or some silica wafer, so
that's very smooth. With mica it would be atomically smooth, with silica wafer it's very, very
smooth, less than one nanometre roughness. Then depending on which instrument we're studying that
interface with we will immerse that surface in a solution where water is the solvent always, in our
case, and the solution also will contain surfactant molecules, where surfactants are like your
everyday detergent molecules.

Robyn Williams: I've got them in my lungs.

Erica Wanless: You have them in your lungs. In fact all of our cell membranes are made of lipids
which are the biological equivalent molecules, but they all have the same characteristic in that
they're driven to congregate at phase boundaries. So we expose the solution containing these
surfactant molecules to that surface and we use optical reflectometry, basically to count the
number of molecules that are sitting at the interface.

Robyn Williams: You can actually count molecules?

Erica Wanless: You get a concentration of molecules at the interface.

Robyn Williams: So you're making a package which is designed to perform a particular function.

Erica Wanless: Yes, we're looking to coat the surface with these polymeric surfactants in solution.
They have pockets of oil-loving core material surrounding by a much more water-loving...we call it
the corona. And what that means is that if you have also in the solution a molecule that would
rather be in an oil-containing environment, it would be driven to the core of these nanometre-sized
objects.

Robyn Williams: So you've got something in a little container hidden there and it's formed almost
like a pill.

Erica Wanless: Yes, it's partitioning of the oil-loving material into the core or encapsulated.
That oil-loving material could be something ultimately like a drug, it could be something
ultimately like a topical cosmetic for controlled release of moisturiser. Anything that really
doesn't like to be in water can be micro-partitioned into these little zones.

Robyn Williams: So you put it on and put it in and at a particular time you give the signal and
it's released.

Erica Wanless: Yes, so in our case the signal is usually a change in pH, not a very big change in
pH.

Robyn Williams: Acidity, alkalinity.

Erica Wanless: Yes, and the core can open up and release then those molecules that have been
entrained back into the solution.

Robyn Williams: Why do you want to smuggle them in like that? Why not just put the killer drug or
whatever it is where you want it?

Erica Wanless: In that whole zone of drug delivery, oftentimes, for example, the drug might be very
toxic, so if you can have it encapsulated until it gets to the site of interest then you can use a
lower dose, which is much better for the patient. It also can mean that it's released slowly rather
than getting a huge spike in concentration of that drug which isn't necessarily useful for the
treatment of that disease, and the same thing applies if we're not talking about drugs, if we're
talking about cosmetics or if you look at a lot of...there's a lot of capsules in shower gels or
conditioner to slowly release onto your hair some other material, it's really about delivery from
one place to the next in a controlled fashion.

Robyn Williams: Instead of a blunderbuss.

Erica Wanless: That's correct.

Robyn Williams: When will you have it on the market?

Erica Wanless: This has been quite fundamental studies that we've been working on, but I am talking
with, for example, paint companies. Modern paints are quite high technologies, and in order to have
water based paints that have got ultimately the right gloss and all of these things, you often have
coatings of this type.

Robyn Williams: Give me an idea, if you've got everything from paints to pharmaceuticals, it could
be this area of nano-chemistry, if I may call it such, is a really huge industrial potential.

Erica Wanless: Yes, I'm part of a very big field which is in surface and colloid science, and that
does range in everything from mineral processing, particularly in this country, through to
foodstuffs and cosmetics and drug delivery. So we're not about making new molecules, we're about
harnessing molecules that other people have synthesised and getting them to where they need to be.
If it's in, say, the food industry, making products that have got longer shelf lives. So you don't,
for example, want the fats in your milk to separate, you don't want the solid particles in your soy
milk to separate, you don't want your mayonnaise to separate, and it's the same sort of technology
that we're using here to control interfacial energy.

Robyn Williams: A few weeks ago I had a physical chemist from Friends of the Earth in Europe
warning against nano-particles that seem to be part of the package these days and which might not
be as benign as some people hoped. Have you been looking at that?

Erica Wanless: No, I haven't been. I'm aware of those arguments and, like with any technology, you
have to have all your checks and balances in place, but a lot of the things I'm talking about, it's
nothing new. We're not making nano-particles, we're just possibly controlling how stable they are
in a dispersion. So while, say, the drug industry is going to have very careful checks and balances
through to clinical trials, we need to do that with a whole range of products.

The reason the argument is there is that materials on the nano scale are not necessarily the same
as their bulk parent material, so the reason for that is that very small particles have got a very
high surface area to volume ratio. That means there are many more surface atoms than bulk atoms,
and those surface atoms have got strains in their bonds which mean they're at higher energy. And so
when you get more of those in the population of atoms, even if it's something that might normally
be a rock that's very benign that's sitting out there in nature, if it's in very tiny particles you
have to understand its physical chemistry and surface chemistry to know how it will behave because
it is a slightly different material.

Robyn Williams: Erica Wanless is a professor of chemistry at the University of Newcastle, making
chemical packages at the nano scale.