Nanotechnology has opened up an entire new world of building material solutions.

From self-cleaning windows and flexible solar panels to LED wallpaper and electricity-generating coatings, nanotechnology has raised the bar when it comes to high-spec building products. By creating new and novel applications, this Lilliputian-scale technological supernova can help to ensure better product performance.

An innovation driver
According to www.smartplanet.com, nanotechnology involves the manipulation of matter at a molecular or atomic scale. The chemical company BASF states that nanotechnology is one of the strongest innovation drivers in research and development. “The dimensions are tiny, but their potential is huge,” states www.basf.com. Dr Andreas Kreimeyer, a board member and research executive director at BASF, says: “Nanotechnology is indispensable in finding answers to questions emerging from a number of different megatrends.” As such, this technology also plays an increasingly important role in the international construction industry, where innovative paints, coatings and concrete additives present a plethora of possibilities that were previously unheard of.

New building blocks for the built environment
According to Michael Smith, an information specialist at NBS, which forms part of the Royal Institute of British Architects (RIBA), industry proponents say that nanotechnology will have a giant effect on building practices and materials. The market research group Freedonia expects the demand for nanotechnology to grow up to US$100 billion by 2025 – of this, construction is expected to claim about 7%.

Nanotechnology in building materials
According to Smith, nanomaterials are still expensive when compared to conventional materials. As such, they are not likely to feature in high-volume building materials. “The day when this technology slashes the consumption of structural steel has not yet been contemplated. Nonetheless, the ‘nano’ tag is showing up more often in building products,” said Smith.

Two nanoparticles that are often used in construction materials are:

  • Titanium dioxide (TiO2): This nanoparticle is being used for its ability to break down dirt or pollution, and then allowing it to be washed off by rainwater on everything from concrete to glass.
  • Carbon nanotubes: They are being used to strengthen and monitor concrete.

Nano-advances in building materials
Exterior and structural applications

A concrete solution
With the quick turnover time of projects, contractors and specifiers seek concrete that doubles early strength, increases productivity and quality production, with the added benefit of contributing to more sustainable construction practices.

Technology-driven companies have developed an innovative hardening accelerator for concrete that helps to speed up concrete hardening significantly – at least double strength at low, ambient and heat-curing temperatures.
 
Traditional acceleration methods, such as heat application or normal accelerators, could interfere with the final engineering properties of the concrete. However, nano-enhanced concrete does not. In addition, it helps to save time, is energy-efficient and offers an attractive overall cost-saving potential.

The hardening accelerator consists of inorganic nanoparticles in the form of calcium-silicate hydrates that are added to the concrete. These act as crystallisation seeds and speed up the concrete-hardening process. The concrete now no longer has to be heated to 50-60ºC to become hard within a certain time.

Anti-aging facades
Researchers have developed a nanotechnology-based novel binder that keeps buildings looking freshly painted for longer. Tiny inorganic silicate particles are homogeneously incorporated into organic polymer particles of water-based dispersions. This nanocomposite dispersion method is mainly used in facade coatings. The coating remains breathable and does not have to be repainted as often. It is also more dirt-resistant, has a more stable colour composite and can withstand severe weather conditions without cracking or chalking, according to www.basf.com.

Smart windows
Using a new nanocrystal material, researchers at the Lawrence Berkeley National Laboratory (LBNL) in the United States of America (USA) have come up with a coating that improves windows’ energy-efficiency, according to www.smartplanet.com. Thanks to the nanocrystal technology the windows can adjust to exterior solar radiation, which help regulate the buildings heat consumption. The technology can be used on windows for residential buildings, greenhouses and thermal-controlled satellites. The process, dubbed “sting coater” technology, is used to spread the nanocrystals evenly on the surface layer. The sting-coater continues to spin until the nanocrystals dry, providing an evenly-spread layer.

And it could be a cost-savvy alternative to traditional materials. “A big issue for new window-coating technology is to make sure that the cost is low enough that it’s available to all the people who might want to buy it and improve the efficiency of their buildings,” said Delia Milliron, a scientist at LBNL.

Interior applications
Illuminated walls
Lighting design reached a new, tech-savvy peak with LED wallpaper. Ingo Maurer, a lighting designer, has partnered with a high-end wallpaper manufacturer, Architect Papers, to create the LED paper, which holds printed circuit boards containing 840 integrated LEDs in five patterns, according to www.metropolismag.com. A range of the LEDs used in the paper shines in red, blue and white. As such, the owner can adjust the hue to suit a mood. The LEDs can also be dimmed to establish the desired ambiance.
Researchers at Sweden’s Linköping University have also developed nanotechnology to print LEDs, which would conceivably lower the bar further for finding innovative ways in which LED could be integrated into wallpaper and other interior design materials.

Self-cleaning restrooms
The Japanese manufacturer Toto has unveiled a product that promises to keep itself clean and germ-free. A similar product – an ultrathin, large-scale ceramic board – also made its debut in Asia recently. The ceramic board has a hydrophyllic, photocatalytic technology that is stain- and odour-resistant.

Catching on in Japan and Europe, these bathroom surfaces have an active ion-oxygen layer that stays clean as more light filters into the room. According to www.smartplanet.com, this technology has huge potential with the current focus on the lifecycle analysis of green buildings.

Highly-insulating vacuum facades
Late last year, product developers at Germany’s Fraunhofer Institute for Process Engineering developed new working prototypes of vacuum insulation panels (VIPs). Made from pyrogenic silica and high-tech thin films, the VIP’s inner components have the same insulation capacity as (or even better than) a traditional insulated facade that is ten times as thick. At this stage the production methods are costly and time-consuming, but as the international economic climate changed, this product may soon provide a viable alternative to traditional products.

New applications
The following nano-enhanced products are likely to be more widely available soon:

  • Surfaces and coatings: A number of companies are using nanotechnology to add special characteristics to product surfaces, which can be anything from stain-resistance and colour durability to self-cleaning, improved hardness and scratch-resistance, corrosion and ultraviolet (UV) resistance and improved thermal performance. Nanotechnology also has the potential to bring antimicrobial properties to surfaces.
  • Thermal performance: By tweaking molecular properties that affect thermal performance, manufacturers have been able to improve this quality in some materials, offering potential energy-efficiency benefits to buildings. Aerogels, very lightweight solids made from silica and carbon, are a high-performing thermal product that benefits from nanotechnology.
  • Structural materials: Carbon nanotubes, for example, offer strength and lightness and are a natural fit for nanotechnology in buildings. Recent nanotechnology research in forest products that focuses on the nanoscale properties of wood hopes to develop advanced nanomaterials. Wood densification, chemical modification or impregnation by resins could improve hardness, wear- and decay resistance.

The future
While nanotechnology has not yet become as pervasive as past materials revolutions, such as plastics, the future seems bright. Researchers suggest that nanotechnology will increasingly help the construction industry to improve the performance of its buildings. Architects and specifiers can look forward to materials that block ultraviolet and infrared radiation, as well as smog-eating products and paints.

For the time being, cost and the relatively small number of practical applications hamper much of the prospects for nanotechnology in the built environment.

However, materials are the core business of construction, and the prospects for change are significant in the not too distant future. The sheer size and scope of the construction industry means that the accompanying economic impact will be huge.

But there is a downside. Many scientists have noted that there could be health risks in using non-materials.  Costs are high, when compared to their traditional counterparts.

Seeing nanoparticles
Until scientists were able to view matter on a nanoscale, it was impossible to manipulate materials at that level. It was also impossible to view the results of experiments and measure their properties effectively, according to www.thenbs.com. Optical tools, along with tools for working with matter at the nanoscale, such as electron-beam lithography, were only truly developed during the 1980s and 1990s.

Carbon nanotubes (CNT), possibly the first application of nanomaterials, look like a fine black powder to the human eye. Viewed through a microscope, the tubes are hollow fibres that can be over a million times as long as they are thick. Their structure gives them a massive strength-to-weight ratio. When blended with polymers, they can add strength to various substances. They are also good conductors and are used at a much finer level in electronics.

However, it seems that nanotubes are not a new substance – Damascus swords apparently contain carbon nanotubes, which might contribute to the legendary sharpness and strength of this medieval steel.

Unique properties
 “When a large particle is divided into smaller and smaller pieces, the proportion of its surface area to its mass increases. This happens at an exponential rate when the particle size is 100nm or less. Since the magnitude of many chemical reactions is limited by the available surface area of the chemicals involved, nanotechnology can make far more efficient use of chemicals,” says Smith. This characteristic can have fairly predictable effects, as well as explosive ones. For example, aluminium nanoparticles, which are usually relatively inert, are explosive, according to www.thenbs.com.

Unique benefits
Controlled production of nanoparticles and the ability to shape materials at the nanoscale have opened up endless horizons. Instead of trying to create nanoscale machines, most nanotechnology in commercial use today simply uses the benefits of nanoparticles.

Full acknowledgement and thanks are given to www.basf.com, www.thenbs.com, www.smartplanet.com, www.metropolismag.com, www.bharatbook.com and www.euronanotrade.com for providing the information to write this article.