Dr Amanda Barnard, computational physicist

Computational physicist

Amanda Barnard was born in 1971. In 2001, she graduated from the Royal Melbourne Institute of Technology (RMIT) University, with a first-class honours science degree, majoring in applied physics. Barnard was awarded a PhD (2003) from RMIT for her computer modelling work, which predicted and explained the various forms of nanocarbon at different sizes.

Barnard then began a distinguished postdoctoral fellowship at the Center for Nanoscale Materials in Argonne National Laboratory, USA (2003-05). She was then awarded a Violette & Samuel Glasstone Fellowship and an Extraordinary Junior Research Fellowship that allowed her to purse research at the University of Oxford, UK (2005-08). During this time, Barnard was using computer simulations to determine what environments were needed to engineer specific types of nanoparticles. This line of research led her to investigate the potential risks of nanoparticles outside the laboratory environment. This is an ongoing theme in her research. Since 2009, Barnard has been working as a research scientist at CSIRO Material Science and Engineering.

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Interviewed by Dr Cecily Oakley in 2010.

Contents


Early studies in physics

Let’s start at the beginning of your scientific career. What did you study at university?

I decided to study applied physics, I liked the mathematics associated with physics as opposed to some of the other sciences. Applied physics, in particular, is related to real world problems, which I found quite attractive.

So you did your bachelor’s degree in applied physics. Did you change when you did your PhD?

I did a PhD in theoretical condensed matter physics. But this is really just the tools of the job; whether you’re doing experimental physics or theoretical physics is just how you go about solving the problem. The notion of applied versus basic is really whether or not we are working on something hypothetical that could lead to some great new technology or something that we already know has an end use in mind.

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Teeny tiny nano

For your PhD thesis, you looked at computational modelling of carbon nanostructures. Perhaps you can explain for us, what is a carbon nanostructure?

Yes, of course. First of all, it’s made of carbon and there’s a range of different structures that it can form. One very famous carbon nanostructure is the Buckminsterfullerene, which is 60 carbon atoms in the shape of a soccer ball. There is also a carbon nanotube, which is like a one-dimensional fibre as opposed to a little spherical, zero dimensional structure, with the same kind of chemical bonding. Then, if we change the chemical bonding, we can have a range of other types of carbon nanostructures such as little nanodiamonds, diamond nanorods and other types of hybrid structures. Nanodiamonds are just like the big, beautiful diamonds but billionths of a millimetre in size.

Just how small from carbon nanostructures? Perhaps you could give us a comparison of scale.

A nanometre is a millionth of a millimetre. To give us an idea, the head of a dressmaking pin is about a millimetre across; so that’s a million nanometres that will fit across the diameter of the head of a pin. Now, DNA is roughly about two to 12 nanometres in diameter, and most nanoparticles used in new technologies are about that size. So that’s about 3,000 times smaller than a red blood cell and about 10,000 times smaller than a strand of human hair.

Very small indeed!

Yes. We certainly can’t see them. Actually, the only way that we can see them is not with an optical microscope or with our eyes but with an electron microscope. We have to image them with electrons instead of with light.

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Virtual experiments

How do you do your computer experiments? Do you have a special, big computer or is it something that I could do on my home computer?

Interestingly, a little bit of both. Some of the simulation work that I do uses massive super computers, and I need to use tens or thousands of CPUs all working as one to get the job done. The other type of work I do is theoretical, in terms of it being very mathematical, and the equations I can solve on a laptop.

How long does it take to run a computer simulation? Is it done in the click of a button?

Well, it depends upon what kind of structure or what kind of material I’m simulating. Sometimes it can happen in a couple of days or weeks; sometimes it will take months for one simulation to run, and you really don’t want to find that you’ve made a mistake when you get to the end.

No, or have a power failure.

And lose everything!

What can a computational experiment tell us that a wet lab experiment cannot?

There are a couple of different things that we can do in a super computer that we can’t do in a wet lab experiment in a test tube. One is that, in order for us to characterise a wet lab system during a process, we have to stop and then take stock of what’s happened. That is we stop the experiment and test it, stop the experiment and test it. We can’t continuously watch a mechanism or a process in situ throughout the entire evolution of the system. In a super computer, we can actually watch every little step along the way without having to continually stop and check how we’re going.

Another thing that we can do in computational experiments is to look at single particles. In a test tube there are millions and millions and millions of nanoparticles and it’s very difficult to isolate one and just look at its properties; in a super computer we can do that very easily. We can also do one other thing, and that is to look at all kinds of extreme environments that are dangerous for people to work in and dangerous for the lab, and in a super computer they’re perfectly safe; I never get any on me.

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Environment determines size and shape

I mentioned before that you were looking at carbon nanostructures in your PhD. What did you discover?

As I mentioned, there’s a variety of different types of carbon nanostructures, and nature has an amazing ability to select which one it will form naturally at a given size or under different types of conditions. So my PhD was trying to unravel the secrets of why that is the case: how does nature decide what type of structure will be formed under different sizes or different conditions. I was able to show for the first time the actual size-dependent phase transformation between the fullerene-like structures and the diamond-like structures, which have very different properties and chemical bonding.

What sorts of things affect the size and the shape?

Properties that can moderate the type of structure that may be formed include the temperature, the pressure and the type of chemical environment, basically what other kinds of molecules are present.

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Inspiration from work and from home

Were there any university professors or other mentors that inspired you?

Throughout my career I’ve had a lot of inspiration, and some of it has definitely come from university professors. But I have to say that I’ve had just as much inspiration from my own students and my own staff. And a lot of my inspiration comes from people that aren’t even in science. Sometimes I get amazing questions that just come from my friends, my family or colleagues of my husband’s and, in trying to come up with the answers to those questions, it makes me think about science in a different way.

After your PhD, where did you go next?

Actually, it was during my PhD when I was at a conference in Boston that I was approached by Argonne National Laboratory, which is a US government lab, and they asked me to come and interview for a position there. After interviewing, I was offered that position. I hadn’t finished my PhD at that time, so they were nice enough to wait for me for six months until I had completed it so that I could start work there.

You completed your PhD in record time, I understand.

Seventeen months.

The average, I think, is probably closer to four to five years? So congratulations for that achievement.

Thank you. This was under extreme conditions. I was living in Toronto and my PhD was through RMIT University in Australia. So I had no distractions—no­one coming in and asking me if I wanted to go for coffee. It’s amazing what you can get done when there are absolutely no distractions to pull you away from the work.

Then you spent your postdoc in Boston?

It was actually in Chicago; at the labs on the outskirts of the Chicago. It is where the Manhattan Project was.

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Shapely titanium dioxide

Oh, that’s very cool. How did you choose which problem to study in your postdoc?

That’s an interesting story. When I was interviewed, I thought they wanted my skills and expertise in carbon. They had a big program in carbon nanostructures there, and I assumed that’s what I’d be working on; that’s what they led me to believe. When I arrived, however, they had a new project in mind. So I didn’t get to choose; I got given a project to work on. It’s often the case that, when you get your first job, they’ve got a project that they have funding for and they give it to you to work on. You don’t get so much time to choose as you do for a PhD.

What was the project?

It was on titanium dioxide. They have some work there looking at different properties of titanium dioxide nanoparticles and understanding the size-dependent properties. My role in that was to help us understand the shape-dependent properties.

What was known before you conducted your research; and how did your findings contribute to our understanding?

Before I did my work on this project, we understood that there was a size-dependent phase transformation. That means that the structure of titanium dioxide nanoparticles is different from big particles and there is a crossover where one will flip to the other. We knew that there was a lot of uncertainty around exactly where that flip point is. I was able to show that a lot of that uncertainty is related to the shape of the particles and the other part of that uncertainty is related to the different types of chemistry—the different pH of the surrounding solution. If we can control the shape and use the pH, we can very accurately determine when that transformation will take place.

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Modelling nanoparticles in the environment

Can you tell us about your time in Oxford?

I joined Oxford in 2005 and left in 2008. During my time there, I was a Senior Research Fellow in the Department of Materials on a Violette and Samuel Glasstone Research Fellowship and I was also an Extraordinary Junior Research Fellow at the Queen’s College.

Congratulations. What were you working on while you were there?

During that time I was actually working on using simulations and computer modelling to try to predict what kinds of environments we could use to engineer specific types of nanoparticles. But while I was there Professor George Smith, who is a Fellow of the Royal Society, introduced me to the idea that the exact same methods that I was using could be used to actually understand what happens in natural environments—outside of the laboratory, so to speak.

So that we could work out what would happen when a nanoparticle got into the environment.

That’s right; to work out what happens when we take them out of the lab and they’re exposed to air or water. The same methods that I was already developing could be used for that purpose. I thought that was a really good idea.

What did you find? What did happen when you took things out of the lab and into the environment?

This is an area of ongoing research. It is actually a big theme in my research right now. So, in a variety of different types of particles that I’m studying, I am looking at, not only what kinds of synthesis environments they have, but also what happens when they’re exposed to air and water etc.

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Costs and benefits of nano-tech

What are some of the dangers of nanoparticles?

Nanoparticles in themselves may or may not be dangerous, depending upon what type we are talking about. I think the greatest issue here is that a lot of it is unknown. Many things around us can be dangerous. Temperature, for example: if you go over 50 degrees Celsius, it causes cell death; if you go to minus 50 degrees Celsius, that also has bad effects. Temperature is not a problem, because we know what these boundary conditions are and we know how to moderate and protect ourselves. Nanoparticles are the same. Of course, under extreme situations, they can also potentially be dangerous. The issue here is that we don’t know what our boundary conditions are and we don’t know what the ideal operating environments for them are, or storage, and what kinds of exposure limits we should set.

And the work that you are doing will contribute to determining those boundaries?

That’s right. It is helping to determine what those boundaries are: what are the ideal storage and operational environments for nanoparticles. Most of my work is focused on understanding how nanoparticles change when they move from one environment to another. Once we have set the right types of conditions, we need to know what happens if they fall out of those conditions. For example what if we move them out of somewhere where they are controlled and stable to somewhere where they are completely uncontrolled and unstable, like a river.

What are some of the benefits or uses of nanotechnology?

There are three ways that I think nanotechnology is going to help us. First of all, it is going to make things cheaper. A lot of the technology we use contains some very expensive materials; for example, gold and platinum. Platinum is a rare earth and it’s called ‘rare earth’ for a reason; it’s an expensive commodity. Now, nanoparticles can deliver us the same kinds of properties but, because the particles are millionths of millimetres in size instead of much larger, we need much less of the material. In the case of platinum catalyst, for example, we need much less platinum to get the job done. So, that’s going to be cheaper.

Secondly, nanoparticles can deliver us greater efficiency. In some cases, they are going to have properties that are the same as the ones that we are familiar with but with a much greater enhancement than what we are accustomed to in bulk materials. We can have, for example, greater energy efficiency, even though we’re just using them for the same types of things.

The third one is that they are going to have a range of properties that we have never seen before. So we are going to have new technologies that we haven’t had in the past; an example is self-cleaning surfaces and glasses, etc.

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Science as a group effort

Do you have other people that you work with in your research?

Currently I have two students and two postdocs—and the group is still growing. I also have many, many collaborators. In the research group that I have at the moment, we have a range of different projects and, even though our work is theoretical and computational, each project has a couple of experimental collaborators that are part of it too. One of the most important things in science, I think, is to build strong collaborations and work as part of a sort of interlocking network of people.

So you are really coming at the problem from a number of different angles?

That’s right. The collaborations between theory and experiment are good for a couple of reasons; I find that the most valuable is that they come up with a range of ways of approaching the problem. They may have things that they do not understand and will come to us for help; and we will come up with predictions. But we will have no idea if they are good predictions unless our experimental collaborators are happy to go back to the lab and test them for us.

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Modelling humans

Are there other problems in science that you’re working on by using computational modelling?

Most of our funded work is in the field of nanotechnology. However, I have a little side project that I’m hoping to do something with later this year. It uses the same kinds of simulation methods that I use in looking at interactions of atoms and particles to model humans. For example looking at the issue of women in science or any kind of minority group in a different workforce and understanding how we can sort of turn these numbers around. I can model what kinds of environmental factors we can introduce to increase the number of women in science—but it could also be men in nursing or anywhere in a workforce where there’s a sort of disparity in gender or race or something like that.

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Looking to the past and the future

Where do you see yourself in 10 years time?

I can’t answer where I’ll be in 10 years time and I’d be very disappointed if I could do so, because a lot of that will be determined by where science is in 10 years time. Even through the past 10 years of my career to date, so much has changed. There are all kinds of things that are the cutting-edge science now, that no­one could have ever anticipated 10 years ago. And, if nothing happens in the next 10 years and all I have to choose from are the things that exist right now, I think that will be rather disappointing for more than just me.

What have been the most rewarding or exciting aspects of your career to date?

A lot of my work over past 10 years, off and on, has been with carbon. And a couple of years ago I actually discovered, using some computer simulations, that diamond nanoparticles exhibit different surface electrostatic potential. This is a lot of big words to say that some of their facets have a positive charge and some have a negative charge, and this affects how they interact with all kinds of other molecules and with each other. I was able to calculate and show that they self-assemble. That is all the particles, with these positives and negatives, attract in the way that magnet poles attract or repel, and they arrange themselves into very distinct patterns. We can control these patterns by controlling the charge, for example with changes in pH and things like that. This is being used for some new chemotherapeutic delivery systems in the fight against cancer, which is very rewarding for me. It is a problem that had existed for 20 years before I came along, and now the solution is delivering us some great new technologies.

I can see that it would be very rewarding, to make an impact on people’s health!

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Words of wisdom

Do you have any advice for budding scientists?

Going into science: my advice would be that you need to try to keep your mind open. Never say the word ‘never’. So often throughout my career I’ve heard people say the words, ‘It will never be measured,’ ‘It will never be seen,’ and ‘We will never be able to do this,’ and they all look like idiots at some point. So try to keep your mind open to ideas for as long as you can.

As a woman in science, what do you think are the challenges in establishing a scientific career?

Computer simulations actually predict that the greatest challenge to any disparity in gender in a workforce is the initial numbers entering; so we need a greater number of women starting careers in science. Then, if there is an extra attrition or any women leave science for any reason—it doesn’t have to be just family; it could be for any reason at all—if they don’t come back, we’ll never turn around from that. The numbers continue to go down, no matter what.

Now, this being said, I’ve lived in four countries and it is very different in each one of them, and being a woman in science is quite different. In Australia, it’s not too bad. It’s much worse in Central Europe and England, but it’s much better in North America. So there is an opportunity for women, if they’re prepared to take a risk and move around the world, to try to build a career in a variety of different places and bring what they learn with them, back to Australia.

That’s really good advice. Finally, what skills do you think you need in science today?

I think you need a thick skin. I think, more and more, science is becoming very competitive. We are all competing for the same pages in journals and the same funding, so we need to learn to have a thick skin. It is also working very, very hard. I think when I was young I had the impression that an academic or scientific life was not too stressful; it’s incredibly stressful. So I think also some advice would be to prepare yourself to work very, very hard and be under a lot of competitive stress.

Thank you very much, Amanda, for your time today. It’s been a pleasure talking to you. Congratulations again on your prize and for all your amazing discoveries. I’m sure you’ll make plenty more.

Thank you.

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