Part 2 - Tiny Pictures of Hope That You May Not Believe

An Interview with John Hart, creator of "nanobama"

(Part 2 of 2, link to Part 1)

Can you explain a bit more about the difference between the disordered structures and either the Metropolis (shown here at the left) or Barn images.
All of these architectures were formed in the same way as described in terms of preparing a mask, using the metal catalyst to seed growth, etc.. The Metropolis patterns compared to the disordered patterns are just a result therefore of not only applying the catalyst in an evenly patterned form but also by getting the process much more under control.

However, in the case of the Barn-like structures, the growing CNTs were also subjected to mechanical pressure during growth, that is, their formation was pushed from the outside if you will. For example, the Barn shape shown is formed as the nanotubes are confined to stay within a trapezoidal mould during growth. We can also apply mechanical pressure by other means to affect the sizes and shapes that are formed.

Why do some columns grow taller than others, even within the same form? I’m just curious how the heck you got the Absolut Nano or for that matter the Star Burst images to grow like that (seemingly “tube within a tube” or even other shapes)?
These shapes actually happen by chance. The governing principle in their formation is that there’s mechanical stress along each of the nanotubes. If you have, say, a cylinder growing upward and perhaps the inside of the cylinder is growing faster than the outside of the cylinder, then at some point the nanotubes in the inside – a certain group of them – will break away from the larger mass.

And the combination of the friction of that center portion breaking away and the outside growing at a slower rate will cause the outside to curl outward. So it’s kind of like formation of a flower.

In other cases, the differences that may occur in the growth rates across large numbers of CNTs can cause bending or wrinkling of the forms. It’s a bit technical, but by introducing spatial and temporal gradients in the reaction conditions or by spatially varying the size of the patterns, the shapes can be influenced to grow to different heights or to lean in particular directions. The gallery of self-organized and patterned architectures that we illustrate at www.nanobliss.com exemplifies these techniques.

Are there advantages of using either mechanical shaping or self-organized growth in terms of applications?
I think in general with micro-fabrication that the ability to make 3-D free-form structures is something that has not been done in parallel on the large scale. Sure, you can use small beams of light to make micro-sculptures but the practicality in terms of scaling-up has not been realized. If I wanted to make true 3-D structures in parallel it would be extremely challenging.

This is I think an advantage of these processes in that this technology – especially now that we’re learning more and more about how to control it better – continues to bring it closer to a true manufacturing process. And sure, various dimensional aspects that we can control – for example, forming a series of pyramids or towers or even a series of channels – can be used with particular advantages for certain applications, including micro-machinery or electronics or optics, just to name a few.

With all this in mind: where does the science end and the art begin? Or is it vice versa?
That’s a good question. I think in a lot of ways they’re intertwined.

Sure, there’s a lot of things that we do that are truly scientific, with no artistic intention. The purpose of imaging these structures – and the way that www.nanobliss.com started – was just in that I was taking pictures for my research, particularly because I didn’t have growth conditions in hand as well as we do now. The growth as you can see was more kind of random.

The art began I guess as we started thinking about using these images or taking new ones of the forms we were coming up with for an artistic purpose. Just the natural self-organization of the CNTs gave some artistic value.

Few of the things we’ve illustrated have outwardly been meant to be artistic. Certainly the nanobama’s were one but this was more of a fun project. But I am thinking more about how to develop the artistic side of it, from maybe a business point of view even selling some images or samples. Or creating more art projects.

Really though it’s a great way to help illustrate what we’re aiming for in our research and demonstrate the principles of organization at a nano-scale. If you can create and illustrate things that people can relate to at small scales, it helps them visualize what the process can achieve. Even every day objects can be used to describe the process; for example, if we illustrate the sky-line of a city, there are principles of the fabrication process embodied in the form.

Or for example using structures to generate patterns of light: there are very clearly defined quantum principles in terms of how nanocrystals respond to light and emit certain colors. If you combine this with nanotubes you can control what colors are formed. Case in point: we wanted to try before Christmas – though we just couldn’t find enough time – to make a “nano-Santa” illustration and color it with quantum dots and make it appear to flash either red or green. Granted you don’t get color with SEM, but in this case we wanted to make it at a scale where you could see it with a normal microscope or even with the naked eye.

So does making art ultimately help with your work, either by teaching or even getting attention (not necessarily fund-raising but if yes, why not…)?
I don’t think the artistic side helps with fund-raising at this point but it does help with teaching. It also maybe helps with outreach. I think this is important perhaps from the other side of funding, perhaps in general with The National Science Foundation or something similar, but I don’t think I’ve realized anything in practice this way.

The greatest thing about it is that it connects me with an audience that I would otherwise not reach. I mean, the media attention for the nanobama’s got a bit crazy and it kind of overwhelmed me at first. I realize now why it happened the way it did but I really didn’t think about what could happen in advance when we made them.

But it’s exciting because I mean these pictures have now been seen by millions of people. They were literally everywhere for a while, in newspapers and web-sites around the world, on all continents, popping up in all kinds of places that I’d never expected. And how many people would have ever seen a structure made out of carbon nanotubes?

For us in the lab, sure, it was kind of basic and a kick to make, but it’s just one representation of what we do every day. Maybe it’s not that not novel to us but it is a basic element of nanotechnology, an aspect that so many people have never seen or would not have seen otherwise. So for us it is such a privilege to think that the work we’ve done has been seen by so many people. And if only a handful of people decide to read a bit more about it or maybe even sign up for a course at the University or ask their science teachers at any level, that’s really cool. That’s the big win for us.

There has been some recent criticism in the press recently about the overall health and safety aspects of using nanotechnology. How would you address that?
This is an important and unresolved issue for nanomaterials that are already in use, and for those yet to come, that is, those that will be in use in the future. I think very importantly, we must not be alarmed by the hype. As with any new area of science and technology, we must support research into investigations of long-term health and environmental impacts of nanomaterials, and must be cautious where necessary.

We need to also consider the “use cases” and weigh the benefits vs. these. For example, even if particular nanoparticles or even nanotubes are potentially dangerous, in most uses we wouldn’t ingest them. Just consider computer chips and circuit boards: these contain toxic materials, and of course, we need to consider life-cycle issues as well (e.g., disposal, recycling). But we each have many such cases of these materials in our lives and as long as they’re used correctly, we’re okay. (ZN: visit the Center for Responsible Nanotechnology for more if you’re interested)

If nanotechnology could fulfil your “ultimate dream” – either artistically or otherwise – in terms of it’s benefit of man as well – what would that dream be?
Oh, I wasn’t ready for this question. I should probably already have a good answer ready.

I do think for myself one of the main dreams is to understand the fundamental mechanisms of energy conversion and how to design materials to optimally convert energy from one form to the other. If we can efficiently get energy from one source – like sunlight and store it as hydrogen – that would affect and benefit all of mankind.

Also as I indicated earlier, the benefit’s that are theoretically possible in terms of detection and treatment and understanding of the mechanisms of chronic diseases.

I think these are the two areas that can most broadly affect society. But it won’t stop here. We’ll also learn how to make stronger and lighter and more efficient materials. As indicated on our nanobliss site, because CNTs are cylindrical molecules of carbon atoms arranged in a hexagonal lattice as in graphite, they have incredible potential. Because the carbon-carbon bonds present are very stable and extremely strong, and because CNTs are seamless and have a very small diameter, CNTs have exceptional properties.

For example, high-quality CNTs exhibit several times the strength of steel piano wire at one-fourth the density, at least five times the thermal conductivity of copper, and very high electrical conductivity and current-carrying capacity. Sure, such properties have generated broad interest: for potential applications such as next-generation electronics where individual CNTs are transistors, to even in the use of space-age composites. In this case, literally trillions of CNTs would work together to form the structure of an airplane wing at only a tiny fraction of the same weight. For example, a fully-loaded 747 (~ 400 tons) could hang from a 5 millimeter (1/4 inch) diameter rope made from continuous parallel CNTs!

But it’s not only in these areas that we are looking to improve properties and uses of CNTs. We also exploring the possibilities to use materials that are made out of natural components, like natural fibers, plants and wood. This is just another aspect of closing the gap between what we as humans can do and what nature can do.

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As John indicates on his web-sites, beyond the fun he and his team had with the nanobama images, carbon nanotubes and other nanostructures are being taken very seriously indeed as potential building blocks for many important technological advances. As mentioned, these include high-performance solar cells and batteries, new methods of diagnosing and treating disease, next-generation computer processors and memory-storage, and lightweight composite materials.

John goes on to indicate that certainly broad awareness and understanding of the widespread benefit’s, implications, and yes, even the potential risks of nanotechnology will be essential for it’s commercial success. Likewise, public and private support for research and education programs catalyzes economic growth and enables continued breakthroughs in energy, medicine, communications, and other vital areas. And again, if this article in some way makes you interested in learning more about nanotechnology, then that’s good, too!

For more, check out the sites mentioned in the article as well as the complete collection of nanobama images at flickr. Also, if you want to check out a “condensed” view of this input, see the following YouTube video (I’m not sure if this counts as getting “scooped” or not, as our interview with John took place in December 2008).

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John Hart is Assistant Professor of Mechanical Engineering at the University of Michigan in Ann Arbor, Michigan. He holds Ph.D. (2006) and S.M. (2002) degrees from the Massachusetts Institute of Technology, and a B.S.E (2000) degree from the University of Michigan, all in Mechanical Engineering. Again, if you want to be wowed, take a look at his résumé.

He has industrial experience in engineering and project management at General Motors, and through various consulting appointments. John received the 2006 MIT Senturia Prize for best doctoral thesis in micro/nano technology, and graduate fellowships from the Fannie and John Hertz Foundation, National Science Foundation, and MIT Martin Foundation. In 2008, John received a DARPA Young Faculty Award (for proposed research on energy harvesting using nanostructures), a R&D100 Award (for the SabreTube Desktop Thermal Processing System), and the Holcim Next Generation Award for Sustainable Construction (for design of energy-saving responsive nanocomposite building skins).

John's research currently focuses on synthesis and applications of nanostructured materials, machine and instrument design. John's nanobliss gallery features his work on scientific visualizations of small-scale structures. Since 2006, John's images have been featured in American Scientist, SEED magazine, PC Magazine, several other international publications and exhibitions ... as well as of course the world’s leading authority on cutting-edge high-technology, namely, Playboy (sorry guys, G-rated only).

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All images and other materials are used with exclusive permission of John Hart. Images and structures made by John Hart, Sameh Tawfick, Michael De Volder, and Will Walker. For more information, please contact John at ajohnh@umich.edu.