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Nanotechnology for

Green Building

Green Technology Forum 2007


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Nanotechnology for GreenBuilding 2007 Dr. George ElvinGreen Technology Forum


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Table of Contents

Executive Summary

Part 1: Nanotechnology and Green Building1. Introduction

1.1 Green Building1.2 Nanotechnology1.3 Convergence

Part 2: Materials2. Insulation

2.1 Aerogel2.2 Thin-film insulation2.3 Insulating coatings2.4 Emerging insulation technologies2.5 Future market for nano-insulation

3. Coatings3.1 Self-cleaning coatings3.2 Anti-stain coatings3.3 Depolluting surfaces3.4 Scratch-resistant coatings3.5 Anti-fogging and anti-icing coatings3.6 Antimicrobial coatings3.7 UV protection3.8 Anti-corrosion coatings3.9 Moisture resistance

4. Adhesives5. Lighting5.1 Light-emitting diodes (LEDs)5.2 Organic light-emitting diodes (OLEDs)5.3 Quantum dot lighting5.4 Future market for lighting


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6. Solar energy6.1 Silicon solar enhancement6.2 Thin-film solar nanotechnologies6.3 Emerging solar nanotechnologies

7. Energy storage8. Air purification9. Water purification10. Structural materials

10.1 Concrete10.2 Steel10.3 Wood10.4 New structural materials

11. Non-structural materials11.1 Glass11.2 Plastics and polymers11.3 Drywall11.4 Roofing

Part 3: Conclusions12. Additional benefits

12.1 Nanosensors and smart environments12.2 Multifunctional properties12.3 Reduced processing energy12.4 Adaptability to existing buildings

13. Market forces13.1 Forces accelerating adoption13.2 Obstacles to adoption

14. Future trends and needs14.1 Independent testing14.2 Life cycle analysis14.3 Societal concerns14.4 Environmental and human health concerns14.5 Regulation

References and links


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cover: flexible solar panel from konarka

acknowledgements: an initial study of energy-efficient nanomaterials was made possible by afellowship at the center for energy research, education and service


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Nanotechnology for Green Building 2007 Dr. George Elvin

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Executive summary

This report offers a comprehensive research review of current and near futureapplications of nanotechnology for green building. Its results suggest that the potentialfor energy conservation and reduced waste, toxicity, non-renewable resourceconsumption, and carbon emissions through the architectural applications ofnanotechnology is significant. These environmental performance improvements willbe led by current improvements in insulation, coatings, air and water purification,followed by forthcoming advances in solar and lighting technology, and more distant(>10 years) potential in structural components and adhesives. U.S. demand for nano-enhanced building materials totaled less than $20 million in 2006, but the market isexpected to reach almost $400 million by 2016. Green building, meanwhile, accountsfor $12 billion of the $142 billion U.S. construction market. 1 The convergence ofgreen building and nanotechnology will result in economic opportunities for bothindustries and, most importantly, significant improvements in human andenvironmental health.

Based on our research, we divide the timeline for nano-enhanced building materialsinto three phases. First, current architectural market applications of nanotechnologyare led by nanocoatings for insulating, self-cleaning, UV protection, corrosionresistance, and waterproofing. Many of these coatings incorporate titanium dioxidenanoparticles to make surfaces not only self-cleaning but also depolluting, able toremove pollutants from the surrounding atmosphere. Insulating nanocoatings promisesignificant energy savings, particularly for existing buildings which can be difficult toinsulate with conventional materials. Already gaining market share rapidly in

industrial applications, insulating nanocoatings will soon have a major impact inarchitecture.

Coming soon are nanotechnologies for solar energy, lighting, and water and airfiltration. Nano-enhanced solar cell technologies such as organic thin-film and roll-to-roll processing are also well under development and will gain an increasing share ofthe solar cell market in coming years. Not far behind is nano-enhanced lighting suchas organic light-emitting diodes (OLEDs) and quantum dot lighting. Marketapplications of these technologies have already begun with small consumer deviceslike cellphone screens, are beginning to enter the architectural lighting market, andwill gain an increasing percentage of that market in the future due to their energy-

saving capabilities. Nanotechnologies for water and air filtration, already widelyavailable as consumer products, will gain an increasing percentage of the market forbuilt-in filtration systems.

In the future, advances in fire protection through nanotechnology suggest greatopportunity as extensive research in this area moves from the universities and researchcenters into commercial production. Extensive research underway on nano-enhancement of structural materials including steel, concrete and wood suggests that


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dramatic improvements are possible in this area, although their marketplaceapplications are, in most cases, many years off.

Public and building industry reaction to nanotechnology has been largely positive sofar. Nanomaterials have already been used in hundreds of buildings, including high-

end projects like the Jubilee Church in Rome by Richard Meier and Partners and NewYorks Bond Street Apartment Building by Herzog & de Meuron. We have evenincorporated several nanocoatings into our office construction at Green TechnologyForum with positive results.

However, a number of factors stand in the way of widespread adoption. Currentobstacles to the adoption of nanotechnology for green building include the high cost ofmany nanotech products and processes, risk aversion and the traditional hesitancy ofthe building industry to embrace new technologies, as well as uncertainty about thehealth and environmental effects of nanoparticles and public acceptance ofnanotechnology. Lack of independent testing and the current reliance on manufacturer

claims in determining the architectural and environmental performance of most nano-products could also hinder adoption.

But as this report reveals, many nano-enhanced products are available today whichoffer substantial architectural and environmental performance improvements overconventional products. Many coatings, for example, can protect building surfaces andreduce the need for harsh chemical cleansers while producing no volatile organiccompounds (VOCs) and even removing pollutants from their surroundings. Ifconsumers embrace nanotechnology as a green technology, if building owners,architects, contractors and engineers accept uncertainty and risk and embraceinnovation, and if the high cost of nano-products continues to fall, the tremendouspromise of nanotechnology for green building will be realized.

As prices for nano-enhanced building products continue to fall, as buyers weigh theirlife cycle and environmental cost advantages, and building industry leaders becomemore familiar with nanotechnology, its widespread adoption seems inevitable.Nanotechnology for green building will reduce waste and toxicity, as well as energyand raw material consumption in the building industry, resulting in cleaner, healthierbuildings. In addition to the human health and environmental benefits nanotechnologyfor green building is poised to make, economic benefits for both the building industryand nanomaterials industry appear considerable. The demand for green building is at aan all-time high, and building owners, architects, contractors and engineers adoptingnanotechnology for green building are likely to emerge as leaders and be rewardedaccordingly for their services. For nanotechnology companies, green buildingrepresents one of the largest markets possible for new products and processes.

The Green Technology Forum report on nanotechnology for green building identifies130 startups and established companies offering or developing nanomaterials for greenbuilding, 54 projects underway at universities and research centers, 43 recent patentsavailable for licensing, and over 250 citations and links to these resources.


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Part 1. Nanotechnology and Green Building

1. Introduction

The design, construction and operation of buildings is a $1 trillion per year market asyet largely untouched by nanotechnology. Demand for nanomaterials in the U.S.construction industry in 2006 totaled less than $20 million. 2 However, as this reportshows, the migration of the entire building industry toward more sustainable greenpractices is a multi-billion dollar opportunity for the makers and suppliers ofnanotech-based materials and products. For architects, engineers, developers,contractors and building owners, new nanomaterials and nano-products offerextraordinary environmental benefits to help meet the rapidly growing demand forgreener, more sustainable buildings.

Nanotechnology, the manipulation of matter at the molecular scale, is bringing newmaterials and new possibilities to industries as diverse as electronics, medicine, energyand aeronautics. Our ability to design new materials from the bottom up is impactingthe building industry as well. New materials and products based on nanotechnologycan be found in building insulation, coatings, and solar technologies. Work nowunderway in nanotech labs will soon result in new products for lighting, structures,and energy.

In the building industry, nanotechnology has already brought to market self-cleaningwindows, smog-eating concrete, and many other advances. But these advances andcurrently available products are minor compared to those incubating in the worldsnanotech labs today. There, work is underway on illuminating walls that change colorwith the flip of a switch, nanocomposites as thin as glass yet capable of supportingentire buildings, and photosynthetic surfaces making any building faade a source offree energy. By 2016, the market for nanomaterials in U.S. construction is expected toreach almost $400 million, twenty times its current volume. 3

1.1 Green buildingThe advent of the nano era in building could not have come at a better time, as thebuilding industry moves aggressively toward sustainability. Green building is one ofthe most urgent environmental issues of our time. The energy services required byresidential, commercial, and industrial buildings are responsible for approximately 43percent of U.S. carbon dioxide emissions. Worldwide, buildings consume between 30and 40 percent of the worlds electricity. 4 Waste from building construction accountsfor 40 percent of all landfill material in the U.S., and sick building syndrome costs an


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estimated $60 billion in healthcare costs annually. Deforestation, soil erosion,environmental pollution, acidification, ozone depletion, fossil fuel depletion, globalclimate change, and human health risks are all attributable in some measure tobuilding construction and operation. Clearly, buildings play a leading role in ourcurrent environmental predicament.

Environmental impact of buildings

Buildings figure prominently in world energy consumption, carbonemissions, and waste. (Source: Levin, Systematic Evaluation andAssessment of Building Environmental Performance (SEABEP),Buildings and Environment, Paris, June 9-12, 1997)

But they also offer a vast opportunity to improve environmental quality and humanhealth. Green building is a catch-all phrase encompassing efforts to reduce waste,toxicity, and energy and resource consumption in buildings. The green buildingmovement has grown to the point that major cities like Chicago and Seattle nowrequire new buildings to comply with strict environmental standards. More and morepublic and private owners are requiring that new construction meet stringentsustainability benchmarks like the U.S. Green Building Councils Leadership inEnergy and Environmental Design (LEED) criteria. The Council of AmericanBuilding Officials' Model Energy Code (residential) and ASHRAE Standard 90.1(commercial) propose tougher energy saving requirements, and the proposed EUDirective on the Energy Performance of Buildings also sets minimum energyperformance standards for new buildings.

atmospheric emissions 40%

energy use 42%

raw materials use 30%

solid waste 25%

water use 25%

water effluents 20%

100%50%0%

percentage of annual impact (us)


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In 2007, the green building sector of the $142 billion U.S. construction market isexpected to exceed $12 billion. 5 And as owners, architects and builders worldwidebecome increasingly committed to green building, a true paradigm shift is emerging,from buildings as one of the primary causes of environmental damage and global

climate change to the industry with the greatest potential to reduce carbon emissions,waste, and energy consumption.

Analyses of global climate change and global-scale plans to alleviate it affirm theimportance of building as our primary opportunity to heal the planet. TacklingClimate Change in the U.S., by the American Solar Energy Society, for example,suggests that 40 percent of the energy savings required to achieve necessary carbonreductions could come from the building sector, with transportation and industryproviding about 30 percent each. 6 Better building envelope design, daylighting, moreefficient artificial lighting, and better efficiency standards for building componentsand appliances are all opportunities to make the building industry the leader in fighting

global climate change and advancing sustainable development and energyconservation.

Green building practitioners seek to implement sustainable development,development that meets the needs of the present without compromising the ability offuture generations to meet their own needs, in the design, construction and operationof buildings. 7 They strive to minimize the use of non-renewable resources like coal,petroleum, natural gas and minerals, and minimize waste and pollutants. Energyconservation is critical to green building because it both conserves resources andreduces waste and pollutants.

But a number of obstacles stand between green builders and these goals. Educationand economics are certainly factors, and efforts are well underway to inform clientsthat initial design and construction costs for green buildings are typically less than 5percent more than the waste- and energy-intensive buildings of the past, and that lifecycle costs for green buildings are actually lower. Policies, regulations and standardsalso play a role, and these are changing quickly in some areas to allow for greeneralternatives like recycled materials and graywater systems.

But for the building industry to achieve its potential as the leader in sustainabledevelopment, new materials are urgently needed. A trip to the lumber yard just a fewyears ago to buy materials for a new deck, for example, would turn up the unpleasantoptions of arsenic-laden pressure-treated lumber, non-renewable old-growth redwood,or environmentally toxic vinyl decking. An effort to conserve energy by installing atticinsulation would meet with the alternatives of fiberglass, polystyrene, or celluloselaced with fire-retardant chemicals, all considered dangerous. Current windows areextremely poor insulators, leading to increased energy consumption. And alternativesto polyvinyl chloride (PVC) pipe for plumbing are healthier than this knowncarcinogen but scarce and costly. Now, however, a new frontier is opening in buildingmaterials as nanotechnology introduces new products and new possibilities.


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1.2 NanotechnologyNanotechnology, the understanding and control of matter at dimensions of roughlyone to one hundred billionths of a meter, is bringing dramatic changes to the materialsand processes of science and industry worldwide. $13 billion worth of productsincorporating nanotechnology were sold last year, with sales expected to top $1 trillionby 2015. 8 In 2004, over $8 billion was spent in the U.S. alone on nanotech researchand development.

Dimensions at the nanoscaleThe diameter of a nanoparticle is to the diameter of a soccer ball as thesoccer balls diameter is to the Earths. (Source: Green TechnologyForum)

By working at the molecular level, nanotechnology opens up new possibilities in

material design. In the nanoscale world where quantum physics rules, objects canchange color, shape, and phase much more easily than at the macroscale. Fundamentalproperties like strength, surface-to-mass ratio, conductivity, and elasticity can bedesigned in to create dramatically different materials.

Nanoparticles have unique mechanical, electrical, optical and reactive propertiesdistinct from larger particles. Their study (nanoscience) and manipulation(nanotechnology) also open up the convergence of synthetic and biological materials


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as we explore biological systems which are configured to the nanoscale. Crossing thetraditional boundaries between living and non-living systems allows for the design ofnew materials with the advantages of both, and it raises ethical concerns. Advances inbiomaterials and biocomposites converge with advances in nanotechnology, and anincrease in their application to construction seems certain to emerge in the future.

Carbon nanotubesCarbon nanotubes can be up to 250 times stronger than steel and 10times lighter, as well as electrically and thermally conductive. (Source:Nanomix)

But with new materials and technologies come new concerns. Uncertainty surroundingthe interaction of nanoscale particles with the environment and the human body hasled to caution and concern about toxicology, worker health and safety, and regulation.Regulations specific to nanomaterials and products have been slow to emerge, partly

due to the inherent difficulty in regulating materials based on particle size, as well aslack of public outcry in favor of stiffer regulation and the success so far of self-regulation by industry and the avoidance of any nano-disasters.


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1.3 ConvergenceIt is not as though nanotechnology will be an option; it is going to be essential forcoming up with sustainable technologies. advises Paul Anastas, director of theAmerican Chemical Society Green Chemistry Institute. 9 The nanotech communityappears ready to meet Anatsas challenge, and the market for nano-based products andprocesses for sustainability is expected to grow from $12 billion in 2006 to $37 billionby 2015. 10 New materials and processes brought about by nanotechnology, forexample, offer tremendous potential for fighting global climate change. According tothe report, Nanotechnologies for Sustainable Energy, by Research and Markets,Current applications of nanotechnologies will result in a global annual saving of8,000 tons of carbon dioxide in 2007, rising to over 1 million tons by 2014. 11

Globally, nanotechnologies are expected to reduce carbon emissions in three mainareas: 1) transportation, 2) improved insulation in residential and commercialbuildings, and 3) generation of renewable photovoltaic energy. 12 It is worth noting thatthe last two of these three areas are centered in the building industry, suggesting thatbuilding could in fact lead the green nano revolution.

Many nano-enhanced products and processes now on the market can help create moresustainable, energy-conserving buildings, providing materials that reduce waste andtoxic outputs as well as dependence on non-renewable resources. Other products stillin development offer even more promise for dramatically improving theenvironmental and energy performance of buildings. Nano-enabled advances forenergy conservation in architecture include new materials like carbon nanotubes andinsulating nanocoatings, as well as new processes including photocatalysis.Nanomaterials can improve the strength, durability, and versatility of structural andnon-structural materials, reduce material toxicity, and improve building insulation.

Nanotechnology markets 2007Building construction is not yet a significant market for nanotechnology.(Source: Cientifica, Nanotechnologies and energy whitepaper, 2007)

chemical 53%

semiconductor 34%

electronics 7%

aero/defense 3%

pharma/health 2%

automotive 1%

food


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Rank Technology

1 Electricity Storage

1 Engine Efficiency

2 Hydrogen Economy

3 Photovoltaics

3 Insulation

4 Thermovoltaics

4 Fuel Cells

4 Lighting

6 Lightweighting

6 AgriculturePollution Reduction

7 Drinking WaterPurification

8 EnvironmentalSensors

8 Remediation

Ranking of environmentally friendlynanotechnologiesMost environmentally friendly nanotechnologies are well-suited to usein buildings (Source: Oakdene Hollins, Environmentally Beneficial

Nanotechnologies, 2007)

The chart and table above reveal that building construction is not yet a significantmarket for nanotechnology. But that is not necessarily bad news for either theconstruction industry or the marketers of nano-products. The construction industry haslong been slow to adopt new technologies, and the nanotech era is proving to be no


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exception. The demands of public and private building owners for greener materials,demands increasingly being enforced as regulations in many instances, will soon forcearchitects and engineers to specify greener materials in buildings. This demand,combined with the environmentally friendly character of most nano-products forarchitecture, will create a synergy that we expect will result in a boom in demand for

nanotechnology for green building.


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Part 2. Materials

2. Insulation

The market for green building materials and technologies will of course be determinedmore by market pull--the needs of architects, owners and contractors--than by thetechnological push of new nanomaterials discovered and developed in the laboratory.But the convergence of green building demands and green nanotechnology capabilitiesover the next 5-10 years appears very strong. It suggests eight categories ofnanotechnology for green building that are the focus of this report.

InsulationCoatingsAdhesivesSolar energyLightingAir and water filtrationStructural materialsNon-structural materials

The demand from both public and private enterprise for more energy efficientbuildings will lead to significant growth in the insulation sector in the next few years.Valued at $7.2 billion value in 2005, it is expected to reach $9.5 billion by 2010. 13

Current building insulation is estimated to save about 12 quadrillion Btu annually or42 percent of the energy that would be consumed without it. 14 Building insulationreduces the amount of energy required to maintain a comfortable environment.Reduced energy consumption, in turn, means reduced carbon emissions from energyproduction. Insulation is, in fact, the most cost-effective means of reducing carbonemissions available today.

Improving on current building insulation could save even more energy and carbonemissions. EU households, for instance, are responsible for one quarter of EU carbonemissions, roughly 70 percent of which comes from meeting space heating needs.Space heating savings through better insulation in Germany, The Netherlands, Italy,

UK, Spain and Ireland, would reduce EU carbon emissions by 100 million metric tonsper year. 15 As the table below indicates, improved thermal insulation could meet over25 percent of EU carbon reduction goals by 2010. In the U.S., improved insulationcould save 2.2 quadrillion Btu of energy (3 percent of total energy use) and reducecarbon emissions by 294 billion pounds annually. 16


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Improvement CO2 Reduction (tons/yr) by2010

ThermalInsulation 174-196

GlazingStandards 50

LightingEfficiency 50

Controls 26

Potential sources of EU CO 2 emission reductionsBuildings have the potential to become leading sources of CO 2 reductions. (Source: CALEB Management Services, "Assessment of thepotential savings of CO 2 emissions in European building stock", May1998)

Todays building insulation industry is in many ways a model of large-scale industrialrecycling. Fiberglass insulation manufacturers are the second largest user of post-consumer recycled glass in the U.S., slag wool insulation typically contains 75 percentrecycled content, and most cellulose insulation is approximately 80 percent post-consumer recycled newspaper by weight. 17

Health effects of several insulating materials are a concern, however, and improvedhealth and environmental performance could lead to greater use and therefore energyconservation. Some sources argue that the fibers released from fiberglass insulationmay be carcinogenic, and fiberglass insulation now requires cancer warning labels.There are also claims that the fire retardant chemicals or respirable particles incellulose insulation may be hazardous. And the styrene used in polystyrene insulation(often known by the brand name Styrofoam) is identified by the EPA as a possiblecarcinogen, mutagen, chronic toxin, and environmental toxin. 18, 19 Polystyrene alsoposes a resource concern because it is produced from ethylene, a natural gascomponent, and benzene, which is derived from petroleum. Two other insulatingmaterials, polyisocyanurate and polyurethane, are also derived from petroleum.

Nanotechnology promises to make insulation more efficient, less reliant on non-renewable resources, and less toxic, and it is delivering on many of those promisestoday. Manufacturers estimate that insulating materials derived from nanotechnologyare roughly 30 percent more efficient than conventional materials. 20


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Nanoscale materials hold great promise as insulators because of their extremely highsurface-to-volume ratio. This gives them the ability to trap still air within a materiallayer of minimal thickness (conventional insulating materials like fiberglass andpolystyrene get their high insulating value less from the conductive properties of the

materials themselves than from their ability to trap still air.) Insulating nanomaterialsmay be sandwiched between rigid panels, applied as thin films, or painted on ascoatings.

Making nanofibers from cotton waste

While cellulose insulation is made from 80 percent post-consumerrecycled newspaper, the equivalent of 25 million 480-pound cottonbales are discarded as scrap every year in the garment industry.

"Producing a high-performance material from reclaimed cellulosematerial will increase motivation to recycle these materials at allphases of textile production and remove them from the wastestream," said Margaret Frey, an assistant professor of textiles andapparel at Cornell.

Frey and her collaborators are using electrospinning techniques toproduce usable nanofibers from waste cellulose. These nanofiberscould form the basis of new insulating materials from cellulosewhich, as the basic building block of all plant life, represents themost abundant renewable resource on the planet. 21

2.1 AerogelAerogel is an ultra-low density solid, a gel in which the liquid component has beenreplaced with gas. Nicknamed frozen smoke, aerogel has a content of just 5 percentsolid and 95 percent air, and is said to be the lightest weight solid in the world. Despiteits lightness, however, aerogel can support over 2,000 times its own weight.

Because nanoporous aerogels can be sensitive to moisture, they are often marketed

sandwiched between wall panels that repel moisture. Aerogel panels are available withup to 75 percent translucency, and their high air content means that a 9cm (3.5) thickaerogel panel can offer an R-value of R-28, a value previously unheard of in atranslucent panel. 22 Architectural applications of aerogel include windows, skylights,and translucent wall panels.


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Currently, major companies in the aerogel arena include the Cabot Corporation(makers of Nanogel,) Aspen Aerogels, Kalwall (using Cabots Nanogel,) and TAASI(makers of Prstina aerogels.)

Brown University currently has several aerogel technologies available for licensing,

including one that can be used as a coating to permit printing on materials thatnormally cannot be printed on. These aerogels can bind various gases for use asdetectors, and can be colored or ground into very small particles and applied like inkusing a printer. They are also transparent and have a low refractive index, makingthem useful as light-weight optical materials. 23

Aerogel: the worlds lightest solidA 9cm (3.5) thick aerogel panel can offer an R-value of R-28. (Source:Sandia National Laboratory)


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Aerogels offer superior insulationAerogels offer 2-3 times the insulating value of other common insulatingmaterials. (Source: Aspen Aerogels)

Nanogel panels provide translucency andinsulationHigh-insulating Nanogel panels are available with up to 75 percenttranslucency. (Source: Kalwall)

aspen aerogels spaceloft

polyisocyanurate foam

polystyrene foam

mineral wool

fiberglass batts

r-value per inch

0 4 8 12 16 20 24


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2.2 Thin-film insulationInsulating nanocoatings can also be applied as thin films to glass and fabrics. MasaShade Curtains, for example, are fiber sheets coated with a nanoscale stainless steelfilm. Thanks to stainless steel's ability to absorb infrared rays, these curtains are ableto block out sunlight, lower room temperatures in summer by 2-3 C more thanconventional products, and reduce electrical expenses for air conditioning, accordingto manufacturer claims. 24

Heat absorbing films can be applied to windows as well. Windows manufactured byVanceva incorporate a nanofilm interlayer which, according to the company, offerscost effective control of heat and energy loads in building and solar performancesuperior to that of previously available laminating systems. By selectively reducingthe transmittance of solar energy relative to visible light, they say, these solarperformance interlayers result in savings in the capital cost of energy controlequipment as well as operating costs of climate control equipment. Benefits includethe ability to block solar heat and up to 99 percent of UV rays while allowing visiblelight to pass through. 25

Stainless steel nanofilm improves UV lightblockageMasa Shade Curtains reduce room temperatures and air conditioning byimproving blockage of ultraviolet (UV) rays. (Source: SuzutoraCorporation)

3M has developed a range of nanotech-based window films that reduce heat andultraviolet light penetration. Their films reject up to 97 percent of the sun's infraredlight and up to 99.9 percent of UV rays. Unlike many reflective films, theirs are metal-free and therefore less susceptible to corrosion in coastal environments and less likelyto interfere with mobile phone reception. These films also have less interiorreflectivity than the glass they cover. 26

masa shade curtain 84%

untreated curtain 58%

uv blockage0% 100%


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Exterior reflectivity can also be controlled by nanofilms. Technology from RensselaerPolytechnic Institute and Crystal IS, Inc. has led to highly anti-reflective coatingsutilizing silicon dioxide and titanium dioxide nanorods for a variety of surfaces. Theircoating has a refelctivity index of just 1.05, the lowest ever reported. 27

Infrared (IR) rays can also be blocked using transparent IR-absorbing coatings forheat-absorbing films for windows. VP AdNano ITO IR5, used in transparent filmcoatings, improves solar absorption properties while maintaining optical transparency,according to its manufacturer, Degussa. The use of AdNano ITO on windows, theyclaim, improves heat management, greatly reducing the energy consumption of airconditioners, thereby lowering greenhouse gas emissions. Production of AdNano ITO,they add, does not pollute the environment with heavy metals, and consumes verylittle energy because drying and calcination take place at moderate temperatures. 28

2.3 Insulating coatingsInsulation can also be painted or sprayed on in the form of a coating. This is atremendous advantage nanocoatings offer over more conventional bulk insulators likefiberglass, cellulose, and polystyrene boards, which often require the removal ofbuilding envelope components for installation.

Because they trap air at the molecular level, insulating nanocoatings even a fewthousands of an inch thick can have a dramatic effect. Nanoseal is one companyalready making insulating paints for buildings. Their insulating coating is also beingused on beer tanks by Corona in Mexico, resulting in a temperature differential of 36degrees Fahrenheit after application of a coating just seven one thousands of an inchthick. 29

Industrial Nanotechnology, the makers of Nansulate HomeProtect Interior paint,advertise that the average surface temperature difference when applied correctly isapproximately 30 degrees Fahrenheit for three coats. For Nansulate HomeProtectClearCoat, they claim an average surface temperature difference of approximately 60degrees Fahrenheit. Nansulate PT is being applied to aluminum ceiling panels in thenew Suvanabhumi International Airport in Bangkok, the worlds largest airport. 30

HPC HiPerCoat and HiPerCaot Extreme are currently used as thermal barrier coatingsby NASA and NASCAR. Their ceramic-aluminum coating process, they report,reduces radiant heat and ambient underhood temperature in autos by more than 40percent. It also offers a corrosion-resistant alternative to environmentally harmfulchrome-plating. 31

Industrial Nanotech is even developing thermal insulation that will generateelectricity. The thin sheets of insulation use the temperature differential that insulationcreates as a source for generating electricity. The fact that there is almost always, dayor night and anywhere in the world, a difference between the temperature inside abuilding and outside a building gives us an almost constant source of energy


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generation to tap into, said CEO Stuart Burchill. The company is now designing thefirst prototype material and filing patents. 32

NanoPore Thermal Insulation uses silica, titania and carbon in a 3D, highly branchednetwork of particles 2-20 nanometers in diameter to create a unique pore structure.

According to its maker, NanoPore Thermal Insulation can provide thermalperformance unequalled by conventional insulation materials. In the form of a vacuuminsulation panel, It can have thermal resistance values as high as R-40/inch--7 to 8times greater than conventional foam insulation materials.

NanoPores makers claim that its conductivity can actually be lower than air at thesame pressure. Its superior insulation characteristics, they say, are due to the uniqueshape and small size of its large number of pores. Solid phase conduction is low due tothe materials low density and high surface area, and NanoPores proprietary blend ofinfra-red opacifiers greatly reduces radiant heat transfer. 33

Nanoparticles with extreme insulating value can also be incorporated intoconventional paints, as in the case of INSULADD paints. As its manufacturerdescribes it, the complex blend of microscopic hollow ceramic spheres that makes upINSULADD have a vacuum inside like mini-thermos bottles. The ceramic materialshave unique energy savings properties that reflect heat while dissipating it. The hollowceramic microspheres in INSULADD create a thermal barrier by refracting, reflecting,and dissipating heat. 34

Superior insulation with reduced thickness330 cm 3 of Nanopore insulating nanocoating (right) provides the same R-value as 7000 cm 3 of polystyrene (left). (Source: Nanopore Incorporated)

expanded polystyrene nanopore


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Inside an insulating nanocoating

Nansulate Shield is an insulation material designed specifically forthe construction industry. It is an ultra-thin insulation that,

according to its manufacturer, has an R-Value many times higherthan the current best building insulation available. It is ananocomposite insulation composed of 70 percent Hydro-NM-Oxide and 30 percent acrylic resin and performance additive. Aliquid applied coating, the material dries to a thin layer andprovides insulation as well as corrosion and rust protection. Themanufacturers describe their products performance this way:

Thermal conduction through the solid portion is hindered by thetiny size of the connections between the particles making up theconduction path, and the solids that are present consist of very

small particles linked in a three-dimensional network (with many"dead-ends"). Therefore, thermal transfer through the solid portionoccurs through a very complicated maze and is not very effective.

Air and gas in the material can inherently also transport thermalenergy, but the gas molecules within the matrix experience what isknown as the Knudsen effect and the exchange of energy isvirtually eliminated. Conduction is limited because the "tunnels"are only the size of the mean-free path for molecular collisions,smaller than a wave of light, and molecules collide with the solidnetwork as frequently as they collide with each other. The uniquestructure... nanometer-sized cells, pores, and particles, means poorthermal conduction. Radiative conduction is low due to small massfractions and large surface areas. 35

Hydro-NM-Oxide ----------- 10 to 13Polyurethane Foam -------- 6.64Fiberglass (batts) ----------- 3.2Cellulose ---------------------- 3.2 to 3.7

R-value comparison of insulationSimilar to aerogel, insulating nanocoatings likethe active ingredient in Nansulate Shield provide2-3 times the R-value of ordinary insulators(Source: Industrial Nanotech)


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2.4 Emerging insulation technologiesWork is underway at many universities and research centers to develop new insulatingmaterials based on nanotechnology. University of California scientists working at LosAlamos National Laboratory, for instance, have developed a process for modifyingsilica aerogels to create a silicon multilayer that enhances the current physicalproperties of aerogels. With the addition of a silicon monolayer, they say, an aerogel'sstrength can be increased four-fold. This could expand the range of applications foraerogels, which must currently be protected by surrounding panels. 36

At EMPA Research Institute in Switzerland, work is underway to create vacuuminsulated products using plastic films such as PET, polyethylene and polyurethanetreated with an ultra-thin coating of aluminum. Only about 30 nanometers thick, thealuminum layer significantly reduces the gas permeability of the film while at thesame time barely raising its thermal conductivity. The resulting cladding layer is thin,homogeneous and gas-tight. The higher cost (still about double that of conventionalmaterials) is offset by the space-saving potential the new materials offer. 37

Many products of current research on nano-insulation are available for licensing. Forexample, eight licensable patents for aerospace insulation materials are availablethrough the Engineering Technology Transfer Center at the USC Viterbi School ofEngineering, including Composite Flexible Blanket Insulation, Durable AdvancedFlexible Reusable Surface Insulation, and Flexible Ceramic-Metal InsulationComposite. 38

Also available for licensing are NASAs Ames Research Centers novelnanoengineered heat sink materials enabling multi-zone, reconfigurable thermalcontrol systems in spacesuits, habitats, and mobile systems. This platform technologycan be adapted to a wide range of form factors thanks to a flexible metallic substrate.

2.5 Future market for nano-insulationIf the field performance of nano-insulation products lives up to manufacturer claims,these products could foster dramatic improvements in energy savings and carbonreduction. However, independent testing of insulating nanomaterials and products inuse will be necessary to verify manufacturer claims and convince potential buyers oftheir effectiveness. Some manufacturers are already making the results of such testingpublic, with encouraging results.

One of the greatest potential energy-saving characteristics of nanocoatings and thinfilms is their applicability to existing surfaces for improved insulation. They can beapplied directly to the surfaces of existing buildings, whereas the post-constructionaddition of conventional insulating materials like cellulose fiber, fiberglass batts, andrigid polystyrene boards typically require expensive and invasive access to wallcavities and remodeling. Nanocoatings could also make it much easier to insulatesolid-walled buildings, which make up approximately one third of the UKs housing


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stock. And unlike cellulose fiber, fiberglass batts, and rigid polystyrene boards,nanocoatings can be made transparent. Their application to existing structures couldlead to tremendous energy savings, and they do not appear to raise the environmentaland health concerns attributed to fiberglass and polystyrene.

3. Coatings

Insulating nanoparticles can be applied to substrates using chemical vapor deposition,dip, meniscus, spray, and plasma coating to create a layer bound to the base material.Other types of nanoparticle coatings can also be applied by these methods to achieve awide variety of other performance characteristics, including:

Self-cleaningDepollutingScratch-resistantAnti-icing and anti-foggingAntimicrobialUV protectionCorrosion-resistantWaterproofing

Thanks to the versatility of many nanoparticles, surfaces treated with them oftenexhibit more than one of these properties. On this versatility and the environmentalimprovements possible through the use of nanocoatings, the European Parliament'sScientific Technology Options Assessment concluded:

"At present, nanotechnologies and nanotechnological concepts deliver a variety ofmostly incremental improvements of existing bulk materials, coatings or products.These improvements point in several directions and often are aimed at improvingseveral properties at the same time. With respect to substitution this means thatnanotechnological approaches often cannot lead to direct substitution of a hazardoussubstance, but may lead in general to a more environmentally friendly product orprocess." 39

3.1 Self-cleaning coatings

Self-cleaning surfaces have become a reality thanks to photocatalytic coatingscontaining titanium dioxide (TiO 2) nanoparticles. These nanoparticles initiatephotocatalysis, a process by which dirt is broken down by exposure to the sunsultraviolet rays and washed away by rain. Volatile organic compounds are oxidizedinto carbon dioxide and water. Todays self-cleaning surfaces are made by applying athin nanocoating film, painting a nanocoating on, or integrating nanoparticles into thesurface layer of a substrate material.


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Self-cleaning facade systems utilizing the latter technology can be found in the JubileeChurch in Rome by Richard Meier and Partners, the Marunouchi Building indowntown Tokyo, the General Hospital in Carmarthen, UK, and Herzog & deMeurons Bond Street Apartment Building in New York. Self-cleaning windows arenow available from most major window manufacturers including Pilkington, PPG,

Saint-Gobain, and Andersen. While the Marunouchi Building and General Hospitalhave self-cleaning windows, in the Jubilee Church titanium dioxide nanoparticles areactually integrated into the precast concrete facade panels. The panel systemsmanufacturer, Italcementi Group, has even tested TiO 2 on road surfaces and found itreduced nitrogen oxide levels by up to 60 percent. At present, their self-cleaningfacade system costs 30 to 40 percent more than regular concrete, but they believe thatself-cleaning materials will save money in the long run. 40

The fiber cement company, Nichiha, employs nanotechnology in three precast panellines for exterior cladding; Canyon Brick, Field Stone and Quarry Stone. Workingtogether with paint manufacturers, Nichiha created a self-cleaning finish on its fiber

cement panels that allows a microscopic layer of water to protect the finish from dirtor soot. A simple rain, they say, will wash away stains leaving the exterior lookingnew. 41

Ai-Nano is, according to its manufacturer, a non-toxic, environmentally friendly,hygienic photocatalytic coating. It creates a semi-permanent invisible coating on mostsurfaces to provide anti-bacteria, anti-mold, anti-fungus, UV protection, deodorizing,air purification, self-cleaning and self sanitizing functionality. 42

Self-cleaning nanocoatings can also be applied as paint, and a variety of commerciallyavailable paints take advantage of TiO 2s properties. Herbol by Akzo Nobel, based onBASFs nanobinder COL.9, displays much lower dirt pick-up and excellent colorretention, according to its manufacturer. They say that during the production of COL.9binders, inorganic nanoparticles are incorporated homogeneously into organic polymerparticles of water-based dispersions. These then form a three-dimensional network inthe facade coating which ensures an extremely hard and hydrophilic surface(causingwater to sheet) and a good balance between moisture protection and water vaportransmission. With Herbol-Symbiotec, falling water droplets wet the substrate evenly,meaning the facade dries faster and picks up less dirt. Similar paints containing TiO 2 are manufactured by Behr, Valspar, and a number of others.

Nanotec offers a range of nanocoatings with varying functionalities. TheirNanoprotect product creates a self-cleaning effect on glass and ceramic surfaces. Theyreport that nanoparticles in Nanoprotect adhere directly to the material molecule andallow the surface to deflect dirt and water.

Self-cleaning windows were one of the first architectural applications ofnanotechnology. The special hydrophilic coating on Pilkington Activ self-cleaningglass, for example, causes water to sheet off the surface, leaving a clean exterior withminimal spotting or streaking. Using daylight UV energy, the photocatalytic surface of


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Pilkington Activ gradually breaks down and loosens dirt, allowing it to be washedaway by rain or hosing. 43

Nanocomposite polymer makes paint last longerFacades coated with Herbol-Symbiotec paint based on BASFsnanobinder COL.9 display reduced dirt pick-up and improved colorretention. (Source: BASF)

According to one report, nanotech surface treatments for stainless steel can reducecleaning time by 80 to 90 percent and protect against pitting corrosion and metal oxidestaining. Permanent coatings with corrosion protective properties are available but arenot offered as an aftermarket product, the report says, and the average lifetime of suchtreatments is between 1 and 3 years. Certain application and curing processes requirespecial devices and machinery which can only be offered during manufacturing. It iscertain, the report concludes, that the products under development will replace thepowder coating processes now widely used for corrosion protection. 44

3.2 Anti-stain coatingsIn 2002, Eddie Bauer apparel became the first brand to employ Nano-Tex stainresistance technology in its designs. Protests by Topless Humans Organized for


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Natural Genetics (THONG) at the Eddie Bauer flagship store in Chicago soonfollowed, but today the clothier continues to expand its nano-enhaced line, and Nano-Tex has expanded to bring stain resistance to fabrics and other interior finishes. HONCompany, KnollTextiles, Mayer Fabrics, Arc-Com, Architex, Carnegie, Designtex,and Kravet all employ Nano-tex in their textiles. Unlike conventional methods that

coat the fabric, claims Nano-Tex, they use a process that bonds to each fiber, makingtextiles last longer, retain their natural hand, and breathe normally. This means thatsolid colors, lighter fabrics and delicate weaves can be used in places where spills andstains are likely.

Nanoprotex by Nanotec is a water-based impregnator with very high penetration depthfor textile. The product is repellent to water, and the adherence of foreign matter to thesurface is decreased. The nanoparticles adhere directly to the substrate molecules,deflecting any foreign matter. 45

P2i produces Ion Mask enhancement for many applications, including aircraft cabin

trim, seats, carpets and uniforms. Originally developed as a military technology toprotect soldiers from chemical attack, Ion Mask applies a protective layer, justnanometers thick, over the surface of a material by means of an ionized gas or plasma.Without changing the look, feel or breathability of the fabric, the treated materialbecomes hydrophobic (water-resistant), making coffee and red wine spills roll off thesurface like beads of mercury. 46

Anti-stain technology is also available from CG 2. They incorporate ceramicnanoparticles that bond with the underlying material to create strong chemical forceswhich they say are around one million times more powerful than the purely physicalinteraction that is present in coatings made using standard mixing or depositiontechniques. The particles can be designed for different capabilities such as anti-adherence, scratch resistance, reduced friction, and corrosion resistance. The additionof only 3 percent silica nanoparticles, they report, can increase abrasion resistance byapproximately 400 percent, while using 10 percent silica resulted in an increase ofapproximately 945 percent. 47

G3i has introduced GreenShield, a soil- and stain-repellent textile finish producedusing the principles of green nanotechnology. According to the company, themanufacturing process eliminates waste and uses ambient temperature and pressure aswell as water-based solvents, minimizing the use of environmentally detrimentalchemistries and reducing the amount of product needed to deliver desired properties.The company reports the new finish reduces the use of liquid- and stain-repellingfluorochemicals by a factor of 10 by using what it calls the principle of micro- andnano-roughness, which creates a pocket of air between the liquid or stain and thefabric, thereby preventing penetration into the fabric. GreenShield, they say, alsosafely provides antimicrobial properties and antistatic properties. 48

LuxShield coating for Luxrae Decking protects by controlling moisture, heat andwater content, UV radiation, and stains. LuxShield coating, says it manufacturer, will


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not diminish when exposed to the harsh elements. LuxShield coating is not a sealer,they say. Instead, its nanoparticles adhere directly to the substrates molecules andassemble into an invisible, ultra-thin nanoscopic mesh that provides an extremely longlasting hydrophobic surface. The hydrophobic effect creates an easy to clean protectedsurface with self-cleaning properties. All foreign particles are washed off by rain or

when rinsed with water. LuxShield coating is non-toxic, environmentally-friendly, andUV-stable. It is, they say, resistant to friction and cannot be removed by water, normalcleaning agents, or high pressure equipment. 49

Zirconia nanoparticles are graffitis demise

Graffiti is an expensive social phenomenon, costing about $1.50 to$2.50 per square foot to clean. Last year alone the London tubespent over $15 million and the City of Los Angeles $150 million forgraffiti cleanup. Those costs could go way down, along with the

harmful effects of solvents used in the cleanup, thanks to newnanocoatings developed by Professor Victor Castao, SeniorResearch Consultant at CG 2.

Dr. Castao and his associates developed a novel approach usingnanotechnology to chemically attach zirconia, a hard ceramic, to atypical polymer (PolyMethylMethAcrylate). In their process,ceramic nanoparticles are chemically grown on top of thepolymeric surface, creating a ceramic surface to the exterior, witha much higher wear resistance. A coating of just 130 nm, which is99.9 percent transparent, passed through an ASTM 500 series wear

test, demonstrated an improvement of over 55 percent comparedto uncoated surfaces. 50

Nanoprotect AntiG is a water-based anti-graffiti nano-treatment suitable for concrete,brickwork, sandstone, travertine, granite, natural cast stones, and mineral plaster. Thetreatment consists of a permanent impregnating undercoat and a semi-permanenttopcoat. Graffiti, says the manufacturer, can be easily removed by low-pressure hotwater, without the need for harsh detergents and chemicals. 51

3.3 Depolluting surfacesSelf-cleaning surfaces enabled by nanotechnology offer energy savings by reducingthe energy consumed in cleaning building facades. They also reduce the runoff ofenvironmentally hazardous cleansers. As surfaces self-clean, they are depolluting,removing organic and inorganic air pollutants like nitrogen oxide from the air andbreaking them down into relatively benign elements.


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Depolluting nanocoatings show considerable promise in cleansing indoor air andreducing instances of sick building syndrome (SBS). The World Health Organizationestimates that up to 30 percent of new or renovated energy-efficient buildings maysuffer from SBS. 52 The EPA estimates that SBS costs the U.S. economy $60 billionper year in medical expenses, absenteeism, lost revenue, reduced productivity and

property damage.53

Self-cleaning nanocoatings shed dirt throughphotocatalysisNanocoatings containing titanium dioxide (left) can be self-cleaning ascompared to untreated surfaces (right). (Source: AVM Industries, Inc.)

MCH Nano Solutions, for example, recently introduced Gens Nano, which thecompany describes as a new easy to apply, green, environmentally friendly,transparent coating for exterior applications. Gens Nano uses titanium dioxidenanoparticles to keep the building exterior clean and at the same time purify the airnear and on the surface by breaking down nitrous oxides, formaldehyde, benzene, andVOCs. 54


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A current drawback to self-cleaning photocatalytic coatings utilizing titanium dioxide,however, is that they require sunlight for activation, reducing their effectivenessindoors. As an alternative for indoor applications, coatings using layered double metalhydroxides (LDH), air-cleaning nanocrystals, can be applied to indoor surfaces toimprove the indoor climate and reduce ventilation requirements, thereby improving

the buildings energy efficiency.55

To help overcome the current outdoor-onlylimitation of titanium oxide, researchers at the Institute for Nanoscale Technology inSydney, Australia, are developing a variation that is activated by a standardlightbulb. 56

Outdoors, photocatalytic coatings like the ones used in the Jubilee Church in Romesuggest the possibility of smog-eating roads and bridges for reducing outdoor airpollution. The Swedish construction giant Skanska is now involved in a $1.7 millionSwedish-Finnish project to develop catalytic cement and concrete products coatedwith depolluting titanium dioxide. 57

3.4 Scratch-resistant coatingsBuildings are subjected to a great deal of wear and tear. Surface scratches can reducethe lifespan of many materials and add to the cost and energy required formaintenance and replacement. The susceptibility of many metals, wood, plastics,polymers and glazings to scratching can limit their potential applications in manyareas. Nanocoatings can significantly reduce wear and surface scratches.

Scratch-resistant nanocoatings are already common in the automotive industry. The2007 Mercedes-Benz SL series, for example, sports a protective coating ofnanoparticles that provides a three-fold improvement in the scratch resistance of thepaintwork. DuPont is also working on nanoparticle paint for autos. The paint, licensedfrom Ecology Coatings, is cured using UV light at room temperature, rather than inthe 204 C (400 F) ovens required for conventional auto paint.

"After the UV hits it, it becomes a thin sheet of plastic," explained Ecology Coatingsco-founder and chief chemist Sally Ramsey in a recent interview. "Abrasion-resistanceand scratch-resistance is very much enhanced."

"We are in the early stages of a profound industry change," added Bob Matheson,technical manager for strategic technology production at DuPont. He estimates thetechnology will reduce the amount of energy used in the coating-application processby 25 percent and reduce materials costs by 75 percent. 58

Ecology Coatings makes coatings for metals, polycarbonates, and composites, and hasalso devised a method for waterproofing paper with nanoparticles. In 2005, thecompany granted a license to Red Spot Paint & Varnish to manufacture and sell itsproduct in North America. 59


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Diamon-Fusion International (DFI) offers a patented scratch-resistant nanocoatingtested and approved by a U.S. Army prime contractor, PAS Armored, Inc., for glassand other silica-based surfaces in military vehicles. The coating, they say, willimprove vehicle safety under a wide range of adverse weather conditions. DFIsnanocoating also integrates an antimicrobial property by inhibiting the growth of mold

and bacteria on the treated surface. Like many of the nanocaotings described here, theDFI coating is multi-functional, incorporating water and oil repellency, impact andscratch resistance, protection against graffiti, dirt and stains, finger print protection,UV stability, additional electrical insulation, protection against calcium and sodiumdeposits, and increased brilliance and lubricity. DFIs hydrophobic nanotechnologycan also be found in Moens Vivid Collection, a new line of luxury faucets andaccessories for kitchens and baths, where it will help guard against watermarks anddeposits. 60

Triton Systems manufactures NanoTuf coating, a clear protective coating forpolycarbonate surfaces. NanoTuf coatings are created from a solution of nanometer-

sized particles suspended in an epoxy-containing matrix. They are specificallydesigned to coat and protect polycarbonate surfaces such as eyewear, making them upto four times stronger than existing polycarbonate coatings. 61

Move over diamond: carbon nanorods are worldshardest substance

Diamond is no longer the worlds hardest material. Researchers atthe University of Bayreuth in Germany have created an even hardermaterial they call aggregated carbon nanorods. They made the newmaterial by compressing super-strong carbon molecules calledbuckyballs to 200 times normal atmospheric pressure whilesimultaneously heating them to 2226 C (4719 F). The new materialis so tough it even scratches normal diamonds. 62

3.5 Anti-fogging and anti-icing coatingsTitanium dioxide becomes hydrophilic (attractive to water) when exposed to UV light,making it useful for anti-fogging coatings on windows and mirrors. G-40 Nano 2000

by AVM Industries is an example of a product using this technology. Polymercoatings made of silica nanoparticles can also create surfaces that never fog, withoutthe need for UV light. This coating also reduces reflectivity in glazed surfaces.

The fogging of glazed surfaces is due to condensation. Condensation occurs whenwarm, humid air contacts a cold surface; the moisture in the air condenses and forms alayer on the colder surface. Condensation can be prevented by heating the coldsurface. A team of researchers at the Fraunhofer Technology Development Group


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TEG in Stuttgart, Germany have developed a nanotechnology that warms the surfacewith a transparent coat of carbon nanotubes. When electrically charged, the coatingacts as a continuous heater uniformly covering the cold surface without wires of othervisible heating elements. 63

Nanocoatings can also help reduce the buildup of ice. CG2

makes an anti-icing coatingthat could offer improved environmental performance compared to heating, salts orchemicals often used to remove ice. According to the company, their product is aneconomical anti-ice coating that in independent tests demonstrated a reduction in iceadhesion by a factor of approximately four in comparison to bare aluminum. Potentialuses include any application where even a relatively small reduction in ice adhesion isvaluable and where a large surface area has to be coated. 64

3.6 Antimicrobial coatingsMany of the multifunctional coatings already mentioned incorporate antimicrobialproperties. Others are marketed specifically for their antimicrobial properties.Antimicrobial products are marketed in sprays, liquids, concentrated powders, andgases. The U.S. Environmental Protection Agency says that approximately $1 billioneach year is spent on antimicrobial products. Conventional antimicrobial products cancontain any of about 275 different active ingredients, including biocides, which mayrelease into the environment. Some biocidal ingredients in antimicrobial products poseboth environmental hazards and indoor air quality concerns.

Antimicrobial nanocoatings reportedly offer the benefits of conventional antimicrobialproducts without these environmental and health concerns. Bioni, for example, offersnanocoatings with a combination of antimicrobial and heat deflective properties. Theirlow thermal conductivity and the ability to reflect up to 90 percent of the suns raysreduce heat absorption in coated walls, thereby reducing air conditioning and energyconsumption. 65

Researchers at the Fraunhofer Institute for Manufacturing Engineering and AppliedMaterials Research IFAM in Bremen and at Bioni CS have developed a process forbinding antibacterial silver nanoparticles permanently to paint. According to Bioni, thecoating is certified as emission-free, and can destroy antibiotic-resistant bacteria. Theyreport that their coating has been used in more than 20 hospital projects in Europe andthe Gulf region, including the 40,000 square meter Discovery Gardens project inDubai. As with nanocoatings from other manufacturers, Bioni can cross-link avariety of nanoparticles to add additional functionality such as UV protection andimproved wear resistance to their antimicrobial coating. Mirage Hardwood Floors ofCanada currently uses these cross-linked nanocoatings.


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End of the line for subway-riding germs

"Public transportation is a very common way, we know, of howdiseases ... spread," said Ben Mascall, spokesman with MTR Corp.,which operates the railway in Hong Kong and has bid for two newrail franchises in the U.K.

In response, his company has coated its cars' interiors with titaniumand silver dioxide nanocoatings that kill most of the airbornebacteria and viruses that come into contact with them. The Londontube will soon do the same.

Many surfaces that people touch every day in a subway carry

thousands of bacteria and germs. With news of powerful flu strainslike avian flu and hand-transmissible diseases like colds, publictransportation operators like these pioneers are considering usingnew nano-enhanced disinfectants in their subways. Hong Kong isamong the first cities to apply silver-titianium dioxide nanocoatingto subway car interiors. Preliminary tests show the disinfectantreduced the presence of bacteria by 60 percent. 66

BioQuest Technologies is marketing its BioShield 75, a nanotech- and water-based

antimicrobial with no poisons, as a preventative product for use in homes andbusinesses in hurricane paths. Proactive application, they suggest, will reduce bacteriaand provide an effective solution to microbial problems that continue to exist in homesand businesses after hurricane damage. 67

Antimicrobial nanocoatings can also be incorporated into ceramic surfaces. TheGerman plumbing-fixture manufacturer, Duravit, for example, has teamed withNanogate Technologies to develop a product called Wondergliss. Wonderglisscoating is fired over traditional ceramic glazing to create a surface so smooth thatdirt, germs, and fungus cannot stick to it. In addition, water beads up and runs off thehydrophobic surface without lime and soaps being able to build up. 68

Many paints contain nanoparticles (commonly titanium dioxide) to prevent mildew,including Zinssers Perma-White Interior Paint, Behr Premium Plus Kitchen & BathPaint, and Lowes Valspar.


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Plumbing aint what it used to be

Microban International offers Microban, which they call the firstantimicrobial polymeric, a plastic resistant to germs, molds, yeast,

and mildew. Microban is used in more than 450 products rangingfrom cleaning supplies, paints and caulking to medical products,plumbing fixtures, and other kitchen and bath products. Theirproduct, they say, does not wash or wear off of its material substrate.As one reviewer of the technology put it:

It is easy to imagine this technology producing piping so smooththat it would have little or no friction loss, which would lead tosmaller piping able to carry many more gallons of water at the sameworking pressure as todays piping. Or drain pipe so smooth andslippery that it cannot plug up. Or pipes that never wear out.

Someday, entire plumbing systems may follow natures design of aliving system. Imagine a water piping system that could change itsdimensions based on the flow demand and available pressure likeour own circulatory systems. Septic tanks could generate electricityas they digest waste. Plumbers in the future will no doubt look backand wonder how we got by with such primitive materials and tools.Truly, plumbing aint what it used to be and it never will be again. 69

Nansulate LDX from Industrial Nanotech is designed to encapsulate lead-painted

surfaces, making them inaccessible by providing an overcoat barrier. At the sametime, it provides mold resistance, thermal insulation, and protection against corrosion.Three out of four homes built prior to 1978 contain lead-based paint, and according tothe EPA, residential lead abatement has cost $570 billion and commercial $500billion. In the past fifteen years, encapsulation as an abatement technique has becomea cost-effective alternative solution, typically costing 50 to 80 percent less than leadpaint removal and replacement. 70

Researchers at Yale University have found that carbon nanotubes can kill E. colibacteria. In their experiments, roughly 80 percent of these bacteria were killed afterone hour of exposure. The researchers said nanotubes could be incorporated during themanufacturing process or applied to existing surfaces to keep them microbe-free. Theresearchers also recognized that since nanotubes can kill bacteria, they could have amajor impact on ecosystems. "Microbial function is critical in ecosystem sustainabilityand we rely on microbes to detoxify wastes in environmental systems," said JosephHughes of Georgia Tech. "If they are impaired by nanotubes, or other materials, heconcluded, it is the cause for significant concern." 71 The EPA now regulates nano-products sold as germ-killing, believing they may pose unanticipated environmentalrisks.


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3.7 UV protection Ultraviolet (UV) light can break down many building materials. Wood, for example, isa desirable, renewable building material; it can be recycled and regenerated, and as astructural material, it can reduce heating and cooling loads because it is 400 times lessconductive than steel, and up to 20 times less than concrete. It is also the only buildingmaterial that takes in carbon dioxide and releases oxygen as it grows, working tocounter the effects of carbon emissions. And it contributes far fewer of theseemissions than its non-renewable counterparts, steel and concrete. But wood must beprotected from environmental forces including water, pests, mold and UV radiation.

When the use of wood-preserving chromium copper arsenate was discontinued forresidential uses (in pressure-treated lumber) in 2003 due to environmental concerns,the wood industry began searching for cost-effective, long-lasting, antimicrobialproducts that would allow wood to perform well in outdoor applications. Today,nanocoatings are proving to fill that gap.

Nanoscale UV absorbers added to protective coatings can help keep substrates frombeing degraded by UV radiation. The result is wood that lasts longer with less grayingthan unprotected wood. And the small size of the particles makes it possible to offerhigh protection without affecting the transparency of the coating. Nanovations TeakGuard Marine is one example of UV protection for wood. Nanovations providessustainable wood protection solutions for Teak and other hardwoods. 72

Many other materials can be protected by nanoparticles as well. SportCoatings makesa colorless, odorless Sports Antimicrobial System (SAS) based on AEGIS MicrobeShield, recently tested on synthetic turf fields, sports medicine training rooms, lockerrooms, whirlpools, and wrestling rooms at Virginia Tech. You could tell it workedquickly, said Denie Marie, Facilities Manager of Virginia Techs Rector Field House.Within 24 hours of the application it erased the typical locker room scent. It broughta noticeable freshness to our facilities. SAS provides an invisible layer ofantimicrobial protection they say will not leach any chemicals or heavy metals into theenvironment and will not rub off onto a players skin. 73

Suncoat makes multifunctional adhesive films and nano-adhesive transparentvarnish for UV protection of awnings and window glass. They say their productallows protected surfaces to maintain color quality over a longer period of time, sheddirt, resist scratches, and self-clean. 74 Centrosolar Glas makes Solarglas Clear andSolarglas PRISM glasses that can be supplied with nano-coated anti-reflectiveproperties. 75

Advanced Nanotechnology Limited's NanoZ product is a zinc oxide nanopowdercoating that the company claims provides superior UV protection and anti-fungalproperties to wood and plastic surfaces. At the nanoscale, zinc-oxide particles areinvisible, enabling the creation of transparent varnishes with the same enhanced


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functionality of colored coatings. NanoZ is used, among other things, to provide UVprotection in Bondall Paints. 76

Tekon makes chemical-free treatments for keeping kitchens, baths, stone, glass, andcountertops clean. Their sealing products protect surfaces from viruses, germs,

bacteria, mold, and other harmful toxins. Tekons Bath, Stone, Countertop, andStainless Steel Kits clean, protect and maintain surfaces in kitchens and bathrooms. 77

Seal America sells a variety of nano-based sealants for wood, stone, tile, fabric,masonry, metal and concrete which they say are non-toxic and have no negativeeffects on human health or the environment. 78 Finally, AVM Industries offers ninemultifunctional nanocoatings for metal, wood, concrete and glass. 79

Research currently underway in universities will add even more functionality to therange of UV-protectant products already available. Researchers at the School of ForestResources and Environmental Science at Michigan Technological University, for

example, have discovered a way to embed organic insecticides and fungicides inplastic beads only about 100 nanometers across. Suspended in water, the beads aresmall enough to travel through wood when it is placed under pressure. Theirtechnology has been licensed to the New Jersey-based company Phibro-Tech. 80 Recentpatents for protective nanocoatings include Interior protectant/cleaner composition,by Hida Hasinovic and Tara Weinmann. 81

3.8 Anti-corrosion coatingsThe cost of corrosion in the U.S. is estimated at $276 billion per year. In the FederalRepublic of Germany, 4 percent of the gross national product is lost every year as aresult of corrosion damage. Corrosion takes a toll not only on steel structures, but onconcrete ones, which require steel reinforcing. In fact, 15 percent of all concretebridges are structurally deficient because of corroded steel reinforcement. 82

For protecting metal surfaces from corrosion, chrome plating is becoming anincreasing concern because of the negative health and environmental effects ofchromium. 83 But corrosion can be reduced by coating materials with chemicallyresistant nanofilms of oxides. CG 2 is one of several manufacturers marketingcorrosion-resistant nanocoatings. Their technology consists of homogeneous thin filmsusing alkoxides with chemically attached ceramic nanoparticles. 84

Another system, Corrpassiv Primer epoxy by Ormecon, displayed the best filiformcorrosion results in the history of the institute, in a study by the FPL ResearchInstitute for Pigments and Paints in Stuttgart. Corrosion protection with Ormecon alsooffers environmental benefits by incorporating organic metals that are free from heavymetals. This makes it possible to replace not only lead compounds, chromatetreatments and chromate, but also the zinc-rich coatings that will in the future beclassified as containing heavy metals. 85


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environments. During the lifetime of the coating, they say, maintenance is reduced towiping the surface with a wet cloth. It is also VOC- and acid-free. 89

On the research front, scientists in India have devised a method to protect copper fromcorrosion by coating it with conducting polymers. Their poly(o-anisidine) coatings

reduce copper corrosion by a factor of 100.90

3.9 Moisture resistanceResistance to moisture penetration is critical to the durability of constructionmaterials. Moisture causes rot in susceptible materials and feeds harmful mold andbacteria. Unfortunately, many conventional waterproofing materials, such aspolyurethane, give off harmful volatile organic compounds (VOCs) as they cure.Nanocoatings, in contrast, provide moisture resistance without these harmful sideeffects.

IAQM's Nano-Encap is a breathable antimicrobial sealant that protects wood, sheetrock and other porous materials from moisture. According to its manufacturer, Nano-Encap encapsulates any mold spores that might have settled on building materials andprevents future mold growth. Made up of cross-linking polymers, Nano-Encap bondsitself to the cellulose in wood and paper, eliminating mold's nutrient sources. Thisclear semi-gloss waterproofing protectant also keeps the treated surface cleaner thanits original state and dissipates any moisture present in the material at the time ofapplication. 91

Water is a principal source of damage to concrete as well, and even dense, high-quality concrete does not eliminate absorption of water and soluble contaminatesthrough capillary action and surface permeability. This can cause efflorescence andcorrosion of the reinforcement. Nanovations offers a water-based micro emulsion,called 3001, for reducing water absorption in concrete. It can be applied to the surfaceor blended into the concrete mix. The result, says the manufacturer, is a low waterabsorptive concrete that is salt and frost resistant and cannot be affected byefflorescence, moss or algae. Its penetration properties, they add, are similar to orbetter than solvent-based solutions. 3001 is VOC- and odor-free, and can be applied inany situation without dangerous fumes. Users can avoid the impact of solvent-basedformulas on the environment, including contributing to photochemical smog andoccupational health and safety concerns. 92

Hycrete is an integral waterproofing system that eliminates the need for externalmembranes, coatings and sheeting treatments for concrete construction. With theHycrete Waterproofing System, concrete is batched with Hycrete liquid admixture toachieve hydrophobic performance. Concrete treated with Hycrete shows less than 1percent absorption. Hycrete CEO David Rosenberg said in a Green Technology Foruminterview that Hycrete transforms concrete from an open network of capillaries andcracks into an ultra-low absorptivity, waterproof, protective building material.


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Hycrete also coats reinforcing steel surface with a monomolecular film whileproviding waterproofing properties to the concrete. It reacts with metals in the water,concrete, and reinforcement to form a precipitate that fills the capillaries of theconcrete, repelling water and shutting down capillary absorption. The product is soenvironmentally safe it is the first material certified by Cradle-to-Cradle, a new

program that evaluates and certifies the quality of products by measuring their positiveeffects on the environment, human health, and social equity.

Reduced moisture absorption in concreteHycrete, a Cradle-to-Cradle certified green nanomaterial for integralwaterproofing, greatly reduces moisture absorption in concrete. (Source:Hycrete)

Nanoprotect CS is a water-based solution with a very high penetration depth forconcrete materials. The hydrophobic treatment, says its maker, is long lasting and canonly be removed by damaging the surface. 93 Another exterior coating, Lotusan,possesses a highly water-repellent surface similar to that of the lotus leaf. Itsmicrostructure has been modeled on the lotus plant to minimize the contact area forwater and dirt. 94

Self-cleaning awning fabrics from Markilux are made of Swela Sunsilk Nano Clean,which its manufacturer says is extremely dirt, grease, oil and water repellent. Thehighly dirt repellent finish of the fabric, they add, offers UV protection and ensureslong lasting radiant colors. 95

Because of their vast market applications, water-repellent nanocoatings are a popularsubject of university research as well, and many of these projects are available forlicense. Ohio State University engineers, for example, are designing super-slick,water-repellent surfaces that mimic the texture of lotus leaves for application in self-cleaning glass. 96 Hong Kong University of Science and Technology has available,Novel TiO 2 Material and the Coating Methods Thereof. 97 Other licensable patentsfor waterproofing nanomaterials are available through the Engineering Technology

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Transfer Center at the University of Southern Californias Viterbi School ofEngineering. 98

Interior Protectant/Cleaner Composition is an example of a recent patent in this area,combining natural camauba wax nanoparticles and zinc oxide nanoparticles with a

quaternary siloxane compound. Its protectant composition cleans, protects, preservesand enhances the appearances of leather or vinyl surfaces used for covering items inthe home or in vehicles. It dries quickly and leaves no oily residue behind. 99

4. Adhesives

While not the most glamorous technology, adhesives have revolutionized theconstruction industry. Construction adhesives were, in fact, voted the most significanttechnological advance of the last half of the 20 th century in one survey of industryprofessionals. But many contain environmentally harmful substances likeformaldehyde. Just as we saw with moisture-resistant coatings, however,nanotechnology promises a more environmentally friendly alternative. But consumerseager to adopt these eco-friendly super-adhesives will have to wait for theircommercialization in construction. The Nano Adhesive Co. of Taiwan, for example,makes nanoadhesives, but only for the cosmetics and medical industries. 100

Much of the inspiration for nano-enabled adhesives comes from nature. Adoptingnatures tricks is sometimes referred to as biomimicry. Examples of hownanoscientists mimic nature can be found in the water-repellent properties ofnanocoatings, which take their lessons from the hydrophobic lotus leaf, and in a newgeneration of nano-adhesives now under investigation, which are based on the

remarkable feet of the gecko, which enable it to climb walls and even ceilings.

Several years ago researchers created nanotube surfaces that matched the geckostenacious toes for stickiness, but how to unstick, and thereby create a useful product,has eluded scientistsuntil now. Researchers at Rensselaer Polytechnic Institute andthe University of Akron have created synthetic gecko nanotube tape with four timesthe geckos sticking power that can stick and unstick repeatedly. The material couldhave applications in feet for wall-climbing robots, reversible adhesives for electronicdevices, and even aerospace, where most adhesives dont work because of thevacuum. 101 The Center for Information Technology Research in the Interest of Societyhas also devised gecko-inspired adhesive nanostructures that will increase the

capability of small robots to scamper up rocks, walls, and smooth surfaces.102

Researchers at Rensselaer Polytechnic Institute have devised a new adhesive forbonding materials that dont normally stick to each other. Their adhesive, based onself-assembling nanoscale chains, could impact everything from next-generationcomputer chip manufacturing to energy production. The molecular glue isinexpensive--100 grams cost about $35--and already commercially available, saidproject leader Ganapathiraman Ramanath. 103


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Self-assembling nanoscale chains form nano-super-glueResearchers at Rensselaer Polytechnic Institute have developed a newmethod using self-assembling nanomaterials to bond materials thatdont normally stick together. (Source: Rensselaer/G. Ramanath)

Researchers at the University of California, Berkeley, meanwhile, have developedbiomimetically inspired nanostructures that can stick to wet, dry, rough or smoothsurfaces, and can be peeled off and reused. These materials are also self-cleaning,leave no residue, and are bio-compatible. Their technology is available forlicensing. 104


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Biomimicry: learning from the lotus leaf

Through nanoscience and molecular biology we are learning moreabout how natural systems, organisms, and materials behave, and

nanotechnology and biotechnology give us the tools not only tointervene in those systems, but to create new ones based on theircapabilities.

The lotus leaf is a good example. By studying its molecular makeup,scientists have unlocked its hydrophobic (water-repellent)properties and incorporated them into a new breed of materialscapable of shedding water completely. The NanoNuno umbrella, forinstance, dries itself completely after a downpour with just oneshake. Developers are applying the hydrophobic properties of thelotus leaf in a wide range of products and materials from self-

cleaning windows to car wax.

Nature offers endless lessons that could be applied to futureproducts, processes and materials. By examining the nanoscalestructure of gecko feet, for instance, scientists have created glovesso adhesive a person wearing them can hang from the ceiling. All ofthese lessons will enable us to learn from nature to create systems,materials and devices that are less wasteful and more efficient thanthose available today. Nature does not waste, and throughbiomimicry we will learn to model our own systems with theefficiency, beauty and economy of natural systems.

Scientists are even developing materials that adhere without the use of adhesives.Scientists at the Max Planck Institute for Metals Research in Stuttgart, Germany, havedeveloped materials whose surface structure allows them to stick to smooth wallswithout any adhesives. The extremely strong adhesive force of these materials is theresult of very small, specially shaped hairs based on the soles of beetles' feet. Theirartificial adhesive system lasts for hundreds of applications, does not leave any visiblemarks, and can be thoroughly cleaned with soap and water. Potential applicationsinclude protective foil for delicate glasses and reusable adhesive fixtures. The new

material will soon be used in the manufacture of glass components.105


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