The science of really useful matter

We are no longer limited to applying natural materials cleverly, we can make substances with the properties we want. Olga Wojtas reports

An occupational hazard for professors is having to explain their subject, says Chris Hall. As Edinburgh University's first professor of materials, he is having to do more explaining than most.

"I find the phrase 'useful matter' to be quite as good as any other," he says. "The one thing that is ever present about materials is the idea of usefulness. It is the science of understanding the origin of materials' properties, mechanical, thermal, electrical and so on, and how new materials might be developed that are useful to people."

In the 1960s, signs emerged of a new subject struggling to evolve, somewhere between physics and chemistry. Materials science has established itself over the past quarter century, most notably at the Massachusetts Institute of Technology and at Oxford University, but no Scottish university has set up a department.

Hall believes Edinburgh is now set to redress the balance with a multidisciplinary centre for materials science and engineering, a hub-and-spokes unit that sits on top of the standard departmental structure.

"We have about foundation members, drawn from all the major departments in the science and engineering faculty, who want to work with people from different backgrounds in new research areas," Hall says.

"Everybody here has a 100 per cent appointment somewhere else, but they contribute some of their research activity to the centre's portfolio.

"Almost overnight we have put together an academic grouping that is as big as many materials departments that have been growing for a long time. I think we are very well placed because we have a lot of strengths in the contributing disciplines - we don't have to worry about the quality of what we're doing in, say, biology or physics, so I think we have the ability to be a very effective contributor to this field very quickly."

Hall has a strong background in industry, having moved from the University of Manchester Institute of Science and Technology to work for oil and gas giant Schlumberger. But the wealth of research possibilities emerging from materials science has attracted him back to higher education.

"I spent a lot of time in the past ten years working with university groups on problems that were related to research needs in the oil and gas industry, and one collects a large number of things one wants to do more on that are not a high industrial priority."

One of his interests has been using a synchrotron to understand the properties of rocks, to help oilfield engineering.

"There has been a lot of controversy about the new UK synchrotron, all to do with where it will be built, but not at all about its usefulness," he says. "One often gets the impression that the synchrotron is mainly a biologists' facility, but this is far from the case. A synchrotron provides extraordinary information about the structure of materials, whether these are biomolecules or catalysts or engineering components."

He is now building up research into the weathering of stone that is intended to provide guidelines for architects and conservationists on what type of stone best suits their needs.

"A lot of knowledge already exists, but there are still a number of quite deep research problems to do with our fundamental understanding of how stone decay works, and what the physics and chemistry of it is.

"If you were to ask a stone supplier to predict what would happen if a piece of stone were put in a particular position on a building, I think he or she would be unable to do so. I'm sure in the future we will be able to understand these processes better and take out a lot of the risk."

An Edinburgh team, working with researchers from Umist, has recently discovered that quarry limestone used for building has a natural capacity to repel water. They speculate that this stems from small amounts of "quarry sap", soluble organic material in the natural waters to which the stone is exposed before quarrying. This binds to the calcite, limestone's main mineral, greatly reducing its capacity to absorb water. Research still needs to be done on how well the limestone retains this initial water repellence once it is used for building, but the study may lead to gentler conservation methods, using fatty acids, for example, rather than silicones and resins.

Materials science has developed a vast range of techniques, theories and analytical methods that can be applied to anything from 1800BC coffin paint pigments to aircraft engines, Hall says. But he believes it has entered an era in which it can deliver on promises to create new materials.

"In the past, the material world was a given, and we then tried to be ingenious about how we used it: 'I have bronze, what can I make out of bronze?'," he says.

"Wood can be used for anything from bows and arrows to medieval vaults, but wood is wood is wood. We've now reached the point where we can be very inventive about materials that have new properties."

He sees this as underpinning innovation in many, if not most, technological areas, making materials science and engineering a key part of the knowledge economy. Foresight, European research programmes and the Engineering and Physical Sciences Research Council have all recognised this, but Hall sees less support from the Scottish Higher Education Funding Council, despite its innovative programmes for research development.

"I think Shefc is so wedded to the notion of key interests that it tends to think in industrial sector terms, like food and drink, and optoelectronics," he says. "The kinds of things that cut across all of these, particularly materials, are not something they identify as such."

Growing expertise means that designers and engineers do not need to feel constrained by what exists, but can seek help from materials experts to create what they want. Aerospace engineers, for example, can say they want to increase the working life of particular materials, or request materials they can use at higher temperatures, Hall says.

"I would hope that the education of the next generation of engineers would encourage them to think about what they might wish to be able to do but can't because they are limited by materials."

He admits that he has been disappointed by the response of students when he asks them to imagine the possibilities. "I don't get very good answers. I think it's because this is a rather mind-boggling idea, and people have a limited view about what materials can do."

He believes part of the problem stems from engineering courses tending to teach materials in terms of classical properties of strength and stiffness in, for example, concrete.

"If you take magnetic storage materials for computing, these didn't exist 20 or 30 years ago. These are the new sorts of materials that we should talk to students about at the beginning of courses."

Hall's favourite prediction is the advent of materials that are capable of moving. And he insists this is not science fiction fantasy.

"We are beginning to understand how biological materials are able to respond to stimuli," he says. "We see now that something like muscle action is simply a change in the shape of a molecule. The system seems extremely clever, but it is not beyond imitation. The more we learn about biomolecular engineering, the more we are tempted by the molecular engineering of synthetic materials."

An obvious application is creating artificial muscle for people with disabilities. "But I am sure there would be all sorts of applications that are non-biological. You could make machines that could swim through a central heating system and inspect what was going on there, machines that could do the sorts of things only an ant can do today," Hall says.

"I think this field will absolutely explode over the next five to 20 years."