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If you want to think big, best start thinking small

AGENDA

Manipulating molecules may sound like the stuff of science fiction but the potential benefits of the new science of nanotechnology, such as the development of materials that adapt to their environment, could well revolutionise the construction industry.

Russ Lynch reports

ON MONDAY forward-thinkers from materials firms, consultancies and academia gathered at London's Imperial College for the launch of the Construction Research and Innovation Strategy Panel's (Crisp) report on the potential impact of nanotechnology on the industry.

So little is known about the field that scientists are still arguing about a precise definition, but nanotechnology is concerned with designing and engineering products at a minuscule atomic level.

The word 'nanometre' derives from the Greek word 'nanos', meaning dwarf, and the unit is equal to one millionth of a millimetre. Put into context, a DNA strand spans 100 nanometres, while a white blood cell measures 10 microns - 10,000 nanometres - and human skin is 1 million nanometres (1 mm) thick.

The average contractor might shrug his shoulders, but a glance at the roll of attendees at this week's conference - Lafarge, Castle Cement, Arup, WS Atkins, WSP and Edmund Nuttall to name a few - suggests that the industry is beginning to sit up and take notice.

Some products in the nano-wave - self-cleaning glass being the most prominent example - have already hit the market.

But CRISP's report, A Review of Nanotechnology and its Potential Applications for Construction - backed by the Foundation for the Built Environment, the Office of Science and Technology, and the Department of Trade and Industry - draws attention to the research going on into the real prizes: cheaper, more durable materials that are able to respond and adapt to their environment.

Professor Peter Bartos, director of the Advanced Concrete and Masonry Centre (ACMC) at the University of Paisley, the major centre for research on nanotechnology in construction, said: 'We are working on materials such as cement and concrete to characterise their components on a nano-scale.

'When we can do that and relate characteristics to bulk macro-scale performance, it will lead to the modification of those properties and the production of stronger, tougher, more durable materials.'

The centre is already carrying out pilot trials with cement hydrates, lime mortars, roofing slate and fibrereinforced concrete, with industry watchers keeping a close eye on progress.

Bob Cather, Arup associate director and head of the consultant's materials technology team, said: 'This is something we are looking at to consider what problems it could help us solve. It could be five, 10 or 15 years away, but the technology is on the way. It could have an enormous impact.'

Research is also focusing on responsive materials able to adapt to their surroundings and change their appearance, such as cladding which responds to heat and light to minimise energy use in buildings. The technology could be used to enhance a building's fire protection.

Because all fractures and deterioration begin at the nano-level, research is also progressing towards the creation of sensors that can respond under duress - this could be crucial in monitoring the condition of buildings and structures.

Dr Tim Broyd, chief executive of the Construction Industry Research and Information Association (Ciria), said: 'The stage we're at is winning over the hearts and minds of the industry. But if you have nano-sensors in bearings for bridges that change colour under pressure, then the potential benefits are obvious.

'The prospect of nanotechnology will also change the way we think about construction. Take self-cleaning glass, which is already available: it is a small example, but designers will start thinking: 'How can we design for that?'

Applications will snowball as the technology develops.'

But nanotechnology needs more cash if it is to really take off, which could be a problem, given the traditional lack of money for innovation in the construction industry.

Professor Bartos added: 'The prohibitive cost of the equipment means that at the moment nano-related research in construction in the UK is practically nonexistent.

'Research and development in construction is historically very low and, in the case of nanotechnology, things are hindered by the medium or long-term prospect of a tangible financial return.'

Nonetheless, ACMC is leading a bid of more than 50 participants from across the European Union and beyond to secure funding for a project to unite the fragmented nanotechnology research programmes.

Nearly £1 billion from the EU's Sixth Framework Programme - a research cashpot worth £11.8 billion in all - is earmarked for the field. If the bid is successful, the Network of Excellence of Nanotechnology in Construction will aim to avoid duplicating areas of research and pool access to the extremely expensive equipment needed to carry it out.

CRISP's report also recommends establishing a network of researchers on the subject and calls for shorter studies into the consequences of nanotechnology on design, engineering, materials specification, construction work, facilities maintenance and building performance.

It argues that the onus is on the industry to convince leading companies and their suppliers of the need to invest in nanotechnology to improve their competitive position, and to create a 'technology watch' so that applications in other industries can be tracked for use in construction.

The report's vision of the nano-era - pencilled in for 2020 - is a bold one of lighter, stronger materials, better insulated and self-cleaning buildings, manufacturers who can supply tailor-made materials, and contractors who can put them together with minimal waste and greater predictability.

But can it be done? Dr Broyd believes it can: 'Things are moving, research is going on and things are coming into the market - and in five, 10 or 15 years' time, who knows where we will be?

'People laughed at Bill Gates in the 1970s when he said he would put a computer on every desk in the country.

Most people dream when they're sleeping but watch out for the ones who dream with their eyes open.'

Getting back to nature

FOR ALL the visions of high science and complex laboratories that the word conjures up, nanotechnology is simply the attempt to copy what nature has already developed far more effectively.

The University of Reading has set up a centre for biomimetics to study the ways in which plants and animals have adapted to the environment, and it aims to develop possible adaptations for the construction industry.

Professor Derek Clements-Croome, research director at Reading's school of construction management and engineering, said: 'Aspects such as the extremely delicate, vibrating hairs on the back of a crocodile could be copied for use as sensors.

'We're a long way off self-repairing buildings but we are examining how crabs' eyes reskin themselves. We've also been looking at how the low drag coefficient of the shark's skin, which helps it move through the water; could be used in construction? It's about catching up with nature.'

Nearer the market is German chemical firm BASF, whose selfcleaning spray mimics the natural properties of lotus leaves. Invisible nanoparticles between five and 10 thousandths of a millimetre covering the leaves cause water droplets to roll off the surface under their own weight, carrying dirt with them.

BASF's research team is looking to combine hydrophobic polymers such as polypropylene and polyethylene with nanoparticles in a spray to produce the same effect in buildings.

Even then, the scientists estimate that the spray will be just half as effective as the lotus.

Windows on the world

MOST nanotechnology applications for construction are far from a commercial reality, but an early exponent has already reached the marketplace.

Pilkington launched its Activ selfcleaning glass for the domestic market last September, with an introduction to the commercial sector planned for later this year.

A microscopic layer of titanium oxide is bonded to the glass, giving it 'hydrophilic' properties: the coating prevents the formation of individual droplets, causing water to sheet off the glass. The coating also reacts with ultraviolet radiation from the sun to break down unwanted dirt and prevent it from sticking to the surface.

A Pilkington spokesman said: 'The glass works on a nano-scale. The thickness of the coating on the glass is the equivalent of a 2p coin on the top of the Empire State Building.'