Sometimes the beginning of the year is a little bit … well … boring. Everyone is working out at the gym and eating healthy green foods, and even though the sun still sets at an ungodly hour, all the festive holiday parties are over.  This admirably disciplined January attitude is great for working off all the pfeffernüsse you shoved in your face and chased with rum-laced egg nog at your Aunt Betty’s house in December, but if you’re not careful all of this new-found rigidity and focus could negatively affect your work.  So if you’re looking to spice up your latest facade design and hey – maybe even your life in general this month, then take a gander at this intriguing “multi-layer, polymeric reflective film that reflects 95%+ of visible light” and that can be used to create snazzy chrome-like, multicolored, and metallic effects in plastics (Source: Inventables.com).

Image courtesy UT Materials Lab & 3M

Radiant light film contains no metal whatsoever, so it’s non-corroding, thermally stable, non-conductive, and won’t produce electro-magnetic interference; it’s a well-mannered material that manages to create a striking effect with a minimum of fuss.  Taking a cue from butterfly wings, the colors in the film are created NOT through the use of pigments but rather through a series of microscopic ridges spaced a few hundred nanometers apart. Variations in the spacing of the ridges produce a range of colors (blue to magenta to gold) though the reflection and interference of different wavelengths of light, and as a result the material appears to change hue as you adjust your viewing angle.

Radiant light film is nothing if not versatile: it can be “embossed, die cut, sheet slit, precision cut, surface treated, dyed, coated to be heat sealed, coated with adhesive, printed and extruded into plastics. It can be combined with suitable color substrates to produce various vibrant colors in both reflection and transmission” (Inventables.com).  Hell – you can even turn the stuff into yarn and knit it into a sweater if you’re so inclined, according to manufacturer, 3M.

UN Studio’s La Defense, Almere

Technology: 3M Radiant Colour/Light Film.
Using radiant colour film to create interference colour.

So far the film has found applications in home décor, packaging, automotive trim and accents, computers, mobile phones and advertising media, and inspired by UN Studio, I think we should wrap some buildings with it. And then let’s go have some cookies because we all knew I’d never make it to March let alone 2013 on this ridiculous salad-filled healthy diet and I’m sore from doing pushups.

WU XING

I have filed Radiant Light film under Water and Wood. It’s flexible, reflective, and it interviews well.

Get Radiant Light Film from Inventables.

When I was a small and intensely young person, my parents would drive me down the California coastline to a town called Carmel near Monterrey Bay, where we would hang out on the beach and frolic amongst the slowly rotting kelp and aggressive sea gulls, eat burgers at Flaherty’s Seafood Restaurant (which specializes in seafood, not land food – I was five), and weave in and out of various art galleries until we were tired enough to return to our hotel and fall asleep.

Image courtesy citi-data.com

One time down in Carmel we saw an elephant seal carcass that had washed up on the beach, and on another occasion we passed two wealthy teenage girls furtively snorting cocaine out of a makeup compact as the sun set over the waves.

When I think about Monterrey, I tend to remember those childhood trips or to think about giant kelp and playful otters; coral reefs don’t immediately spring to mind. But Stanford University biomineralization expert Brent Constantz is working to change that with a new demonstration plant in the Bay that works just like a coral reef … but that manufactures cement.

Image courtesy sophiarogge.blogspot.com

Though tiny, “corals are the master builders of the animal kingdom. Powered on plankton and their symbiotic algae, hard corals extract the carbon dissolved in seawater and turn it into their calcium carbonate skeletons” (Guy). These skeletons build up on each other on a massive scale over time, creating rich habitat for diverse sea life that reminds me of what happens when we build cities out of concrete.

Image courtesy Calera.com

Constantz saw the opportunity to learn from nature and developed a coral-inspired cement manufacturing process. Cement manufacturing is a massive source of carbon emissions: in fact, “the cement industry is responsible for 5% of global carbon emissions, with each ton of cement producing a ton of CO2” (Guy). Constantz’s company, Calera, aims to green the production of cement by “capturing flue gases from factories, running them through a saline solution, and using electricity to convert the gases into solids. For 542 million years, corals have been sequestering carbon dissolved in water” (Guy). Calera is looking to reduce the time scale for sequestering carbon dioxide gas that could be affecting our climate.

WU XING:

I have filed this coral-like material under Earth and Water; connect the dots!

Cited:

Earthsky.org “Making Cement the Way Coral Does: Out of Thin Air.” Fastcompany.com Accessed 12/08/11. URL.

Guy, Allison. “Growing Cement like Coral.” NextNature.com 05/12/11. Accessed 12/08/11. URL.

The grass is always greener – except when it doesn’t rain appreciably for three straight months, as was the case this summer where I live in Texas. Here, the grass was golden brown, parched, dessicated and crunchy like a stale sugar cookie or gauze belonging to a dried out ancient Egyptian mummy. As summer wore on, I found myself desperately squinting up at the blazing blue sky, searching in vain for the faintest hint of cloud formation. We were facing the kind of heat that makes standing on black pavement completely unbearable; the asphalt melts rubber shoe soles and causes low level leg hair to spontaneously combust. As I watched the tree leaves bake to brown and tumble end over end to the ground in defeat, I wished more than anything for rain.

Image courtesy http://howlinghooligan.blogspot.com

I imagine that in places like Seattle, or the Netherlands, where Frederik Molenschot and Susanne Happle developed a new water-activated concrete product they call Solid Poetry, people don’t stand around hoping for rain because the odds are good that it’s already falling from the sky. And now that it’s raining again in Texas, I can see many more applications for this innovative, delightful smart material. When dry, Solid Poetry appears dull and chalky – indistinguishable from standard concrete.  But just add water and suddenly hidden decorative floral and leaf patterns appear, lingering only as long as the moisture level at the surface of the concrete remains high.

Images courtesy www.studiomolen.nl

Happle came up with the idea while on a walk, where she observed leaves blow off of wet pavement leaving an inverted shadow image of lighter concrete behind. She writes:

“Whenever the weather changes the landscape transforms; the light becomes different and the whole atmosphere changes. All materials seem to alter. In my project I explore the possibilities for hidden design appearing as the environment changes. I applied techniques to enduring and solid materials as glass and concrete, so that natural processes like differences in temperature causing condense reveal patterns on windows. Rain uncovers decoration on a city square. The possible applications of solid poetry are various: either at home in the bathroom, in the garden, in saunas and dance clubs, where the humidity is high or public spaces like bus stops or pavements. All forms of solid poetry have in common that they change the whole setting; they are surprising and have a life of their own.”

If you’re like me, now that you’ve heard about Solid Poetry you’ll spend more than a few minutes doodling custom patterns for use in a dream bathroom.  But while custom and cast-in place patterns are possible with the system, the prefab repeating modules are what allows Solid Poetry to scale as a mass-produced, store-ready proposition ripe for commercial distribution. To learn more, treat yourself to this short video:

WU XING:

I am filing Solid Poetry under earth because it’s concrete and water because that’s the reason the concrete goes all magic and mystical.

Cited:

“Beautiful Concrete by Solid Poetry” Ronamag. 11/08/11. Accessed 11/29/11. URL.

Yesterday I bent over in the attempt to tie the absurdly bright purple shoe laces on my almost offensively bright purple sneakers and made a startling discovery: I’m not as flexible as I used to be.  In fact, the overwhelming tightness of my hamstrings makes your standard British upper lip look positively floppy; and as I fired up my smartphone to schedule some emergency yoga I was reminded that I had yet to share an amazing new fully stretchable OLED display recently developed at the University of California, Los Angeles, a place where they know a thing or two about screens.

OLEDs or Organic Light-Emitting Diodes are great technology for screens primarily because they work without a backlight and can display deep black levels for high contrast.  OLED displays can be manufactured thinner and lighter than liquid crystal displays (LCDs) and “in low ambient light conditions such as dark rooms an OLED screen can achieve a higher contrast ratio than an LCD, whether the LCD uses either cold cathode fluorescent lamps or the more recently developed LED backlight. Due to their low thermal conductivity, they typically emit less light per area than inorganic LEDs” (Source: Wikipedia). What it all boils down to is that OLEDs are the bees knees. FACT.

Image courtesy wired.com

Once researchers saw how thin they could make OLEDs it was only a matter of time before people starting thinking about how to make them flexible. Stretchable electronics open up a world where video displays get rolled up and stuffed in your pocket, electronic sheets drape like cloth, electronics grow and shrink on command, and the mighty condor gets taken off the endangered species list.

Early attempts at stretchable electronics resulted in prototypes that connected rigid LEDs with stretchable material and others that bent but couldn’t stretch. The challenge researchers faced was how to ensure that the electrode could maintain connectivity while being deformed since many conductive materials can’t stretch nearly as far as one might like.  Enter the humble yet versatile carbon nanotube: it’s stretchable, conductive, appears transparent in thin layers, and it usually picks up the check after lunch dates.

The fly in the nanotube ointment, so to speak, is the fact that carbon nanotubes must be attached to a surface; the attachment can be tricky to pull off since when applied to a plastic backing nanotubes have a tendency to slide off or even slide past each other when the backing is stretched. To evict said proverbial fly from said proverbial ointment, the UCLA researchers created a carbon nanotube and polymer electrode layered on a stretchable, light-emitting plastic.

The researchers “coated carbon nanotubes onto a glass backing and added a liquid polymer that becomes solid yet stretchable when exposed to ultraviolet light. The polymer diffuses throughout the carbon nanotube network and dries to a flexible plastic that completely surrounds the network rather than just resting alongside it. Peeling the polymer-and-carbon-nanotube mix off of the glass yields a smooth, stretchable, transparent electrode” (Grifantini).  I imagine that the carbon nanotubes embedded in the plastic stretch at roughly the same rate, and that the plastic keeps to itself mostly and doesn’t interfere with the ability of the nanotubes to conduct electricity.

Image courtesy pcworld.com

The team sandwiched two layers of carbon nanotube electrode around another plastic that emits light when current runs through it.  Researchers obtained a laminator from a local office supply store to press the layered device together so that it could be handled safely in the presence of electric current.  As an aside, we did the same thing when we screen printed an electroluminescent lamp in Switzerland this summer and were hoping to not get electroshocked by the circuits. (More on that soon).  In contrast to our electroluminescent display, the flexible OLED created by the UCLA team can be stretched by as much as 45 percent while emitting a colored light.

Their prototype is a two-centimeter square that emits a one-centimeter square brilliant sky-blue light that stretches like silly putty until it loses conductivity due to being stretched too far or too many times (Grifantini).  The researchers also made a prototype using silver nano wires (which are more conductive than nanotubes) that exhibits similar stretching properties but is even more conductive.  Their layered approach is a great idea, not least because it’s easy to imagine how the process could be scaled up for production.  Now if only those scientists could help me with my hamstrings….

WU XING:

I have filed stretchable OLEDs under Water, Wood and Fire because they’re flexible, stretchy, and they light up.

Cited:

Grifantini, Kristina. “The First Fully Stretchable OLED.” Techreview.com 08/26/11. Accessed 10/05/11. URL.

Watch video: Stretchable OLED – Tech Review

There wouldn’t be so many spy novels if there weren’t something so delightfully compelling about the idea of being a spy: you’re invited to imagine that your job is to sneak around in a trench coat and fedora, talking out of the side of your mouth and pretending to be something or someone you’re not in order to gather information on behalf of the resistance.

Knowing something you’re forbidden to know, or that other people want to know but don’t – or that other people don’t think you know, imparts a feeling of power and control that is like fresh, unadulterated catnip to a newborn kitten: heady stuff.

Image courtesy mike.shannonandmike.net

When I was younger I spent a lot of time writing cryptic messages in lemon juice on slips of computer paper – which at that time came in continuous sheets bordered by strips with holes and was divided by perforations for use in dot matrix printers. These messages could be passed with great stealth to friends in the school yard, who would then hold the paper over a heat source to reveal the messages. In the presence of heat, the acid in the lemon juice made the paper turn brown wherever it had been applied, thereby allowing dedicated ten year-olds to let each other know that someone had recently acquired a Barbie house.

I guess these days ten year-olds just text or email each other, which is great because it leaves more lemons for lemonade stands and other entrepreneurial activities.  But I am pretty sure the researchers who developed SPAM grew up in a time where analog methods were used to exchange information.  SPAM stands for “stenography by printed arrays of microbes” and it has nothing whatsoever to do with canned meat products.  The idea is that messages are encoded in colors of glowing bacteria, and they can be unlocked with antibiotics.

Image courtesy wikimedia commons

People have been encoding secret messages in living molecules for a while, but SPAM is unique among these methods because it’s simple: it requires “no gene sequencing equipment, microscopes, or other scarce and expensive laboratory gear to extract the coded message. Some simple LEDs and a smartphone would suffice, allowing the recipient to receive the printed microbes through the mail and quickly and easily unlock the message” (Dillow).  So maybe it’s a viable option for ten year-olds after all.

The research team inserted fluorescent proteins into seven different strains of the amazingly useful Escherichia coli bacteria, so that they would each glow in one of seven different colors under the right light.  The engineered bacterial were then grown in sequences of paired dots that represented numbers or letters and imprinted on a sheet of nitrocellulose (Dillow).  This meant that the message could be sent through the post like any other highly flammable piece of paper.

Image courtesy spam.com

The recipient of the message simply regrows the bacteria, places it under the right kind of light or exposes it to antibiotics, and BAM – the coded message reveals itself. The researchers were able to tune the bacteria to only express colors after a specific period of time, to respond to specific antibiotics and not others, and they even created a strain that would die off after a certain period of time.  To put it another way: this means that the message could literally self destruct in five seconds, which makes me absurdly happy (possibly because I’ve watched a LOT of Mission: Impossible over the years.

Although this messaging system is as cool as a tiger frolicking in the cool waters of a river in Southeast Asia, there are some issues: for one thing, a finite number of antibiotics presently exist in the world so messages could be decoded by a straightforward process of trial and error. The researchers behind the technology aren’t troubled by this limitation because they’re less interested in spy drama than you’d expect: “they’re more interested in developing new ways to watermark genetically modified organisms with ‘biological barcodes’ to protect intellectual property and make the world safer for modified life” (Dillow).

I was disappointed to learn that the bacteria are essentially a glowing copyright notice, but the fact remains that this development is rife with potential. In fact, I’m not going to say how I know this but I just found out that someone very close to you recently acquired a Barbie house.

WU XING:

I am filing super-spy bacterial invisible ink under water and earth.

Cited:

Dillow, Clay. “By Encoding Messages in Glowing Proteins, Scientists Turn E. Coli Into Invisible Ink.” Popsci.com 09/27/11. Accessed 10/05/11. URL.

Glass is the best. Glass is the friend who drives you to the airport without complaining, who helps you move your fourteen-ton couch in exchange for beer, who tells you that you’ll regret the neon green mohawk when you look back at your wedding photos. Glass goes the extra mile. Without glass we’d either live and work in rooms devoid of daylight or we’d punch holes in the walls and our homes and offices would be full of weather, confused seagulls, and the occasional ambitious praying mantis.  It would be chaos.

Now imagine if glass could go one better: if glass could get you tickets to the Superbowl, or if it let you drive its Bugatti. In my humble opinion, that day has dawned.

Image courtesy helixated.com

A group of South Korean scientists have developed new glass that “becomes more or less transparent according to the light outside, darkening to save air conditioning bills on hot days, and letting in warmth on cold days to reduce heating costs. But unlike other designs, it does so automatically, without users having to use a control to dim or brighten the effect” (Schiller).  At this point, if you’re a devoted reader of ARCHITERIALS, you’re probably thinking, “but wait wasn’t there that glass that changes color and then that other really cool irridescent glass film? Hasn’t this been DONE??”

Well …. yes.

BUT there are drawbacks to many of the existing varieties of smart glass (electrochromic glass, for instance, or suspended particle displays): “many are expensive, degrade after relatively short periods, or present environmental problems during manufacturing processes” (Schiller).  So if you’re looking for a way to reduce heating and cooling bills but don’t want to degrade the environment by more than the minimum possible, then theoretically this new smart glass might work for you.

The researchers assert that their layered assembly of polymer, counterions, and methanol creates a low-cost, stable window embettered by an ability to switch automatically from transparent to opaque in a matter of seconds (Schiller).  I assume that this is based on the amount of light that hits the glass. In case you are not familiar (I wasn’t): counterions exhibit a charge opposite to the substance with which they are associated.

Image courtesy Chang Hwan Lee, Ho Sun Lim, Jooyong Kim†, and Jeong Ho Cho

So here’s how I understand this: the researchers created an environment where nanocrystalline surface structures either scattered the incident light (producing an opaque effect) or dissolved away, allowing light to travel through the glass.  The assembly is less toxic to produce than other chemical-intensive composites, and rather than requiring an electric current to achieve a transition from opaque to transparent, the material can make the change on its own. Magnificent.

WU XING:

I have filed smart glass under WATER because it makes sense.

Cited:

Schiller, Ben. “Smart Glass Becomes More Or Less Transparent Depending On The Weather.” Fastcompany.com 10/3/11. Accessed 10/4/11. URL.

“Counterion-Induced Reversibly Switchable Transparency in Smart Windows.”  Chang Hwan Lee, Ho Sun Lim, Jooyong Kim and ,Jeong Ho Cho. ACS Nano 2011 5 (9), 7397-7403. URL.

There are three types of people in the world: those who carefully transport insects and arachnids out of the building on sheets of paper, releasing them into the wild to roam free, bite innocent people, and reproduce; those who whip off their hard-soled shoes and gleefully smash anything with an exoskeleton that happens to wander within range; and those for whom the thought of a particularly nasty bug is enough to inspire a scream-enhanced instinctive high-speed run headlong into another room.

I belong to the last category, and thus it is with great trepidation and reluctance that I write about a new body of research out of the University of Akron that examines a pair of spider glues with useful properties.

I’ve read about work people are doing with spider silk threads (the silk tends to be amazingly strong – much stronger than kevlar, for instance, which is the material Superman would have adopted as his benchmark had it been more prevalent back in the day). But until recently I hadn’t stopped to think about what makes spiderwebs such a menace to society and to gnats, namely: they are sticky.

Image courtesy socypath.com

So as it turns out, to my abject horror, there are at least two general types of web-weaving spiders and they use the same set of glands to produce two different types of sticky silk-coating glue.

The first type, orb-weaving spiders, have been around pretty much since the dawn of time, and they produce something called viscid glue, a “glue that acts like a viscoelastic solid. Highly humidity-sensitive, this glue expands in magnitude and demonstrates a monotonous increase in elasticity under increased humidity. The glue also displays a decrease in surface adhesion that results in optimal adhesion at intermediate humidity” (physorg.com). Viscid glue can become stickier or less sticky depending on the humidity level.

The other type of spider, your garden variety cobweb-weaving spider,  is a direct descendant of the orb-weavers but produces gumfoot glue, an adhesive material that differs in structure, properties, and response to humidity.  Gumfoot glue “acts as a viscoelastic liquid that is resistant to changes in humidity, consequently maintaining constant elasticity and adhesion” (physorg.com).  So even when these spiders live in New Orleans or Hotlanta, the glue they produce maintains a consistent level of stickiness.

To figure out how glue from the two types of spiders differed, the research team took individual drops of glue and stretched them at different humidity levels. Observing that viscid glue behaved like a viscoelastic solid and that the gumfoot glue behaved like a viscoelastic liquid, the researchers designed a polymer model of the glue droplets to understand the mechanisms at work behind the responses.

Image courtesy coolphotoideas.com

Understanding the behavior patterns of natural biomaterials, such as spider glue, provides us with insight we can use to develop smart materials and devices that may undergo changes in dimension, properties, and function in response to changes in the environment.  Investigating changes wrought by evolution provides us with a means of advancing biomimetic research (research that seeks to understand and mimic nature, Leonardo DaVinci-style).  This line of thinking could lead to new adhesives with applications in buildings in humid environments, among other things – and that is why I braved a “spider” keyword Google search in order to illustrate this post.

WU XING:

I have filed this adhesive under WOOD and WATER, for reasons known only to myself.

Cited:

“Spider Silk Glue Inspires Next-Generation Technology.” Physorg.com 7/22/11. Accessed 7/22/11. URL.

Vasav Sahni, Todd A. Blackledge & Ali Dhinojwala. “Changes in the Adhesive Properties of Spider Aggregate Glue During the Evolution of Cobwebs.” Scientific Reports 7/21/11. Accessed 7/22/11. URL.

I resent the noise of the printer, printer jams, shaking the toner cartridge, the harsh chemicals involved, and the amount of electricity it takes to print on a sheet of paper. I resent those things with the heat of a thousand suns.

But … just when I believed that I had calcified in my negative stance on all forms of printing, I learned that MIT engineers recently revealed a process they’ve developed to produce printed solar cells.  Their flexible cells can be printed on paper or fabric and folded over 1,000 times without losing efficiency, and they’re not energy-intensive to produce!  I was cautiously optimistic: maybe, I thought, printing doesn’t have to be completely evil?

Photos: Patrick Gillooly/MIT

The creation of typical solar cells involves exposing substrates to intense chemicals and high temperatures, which necessitates a whole lotta energy consumption.  MIT’s new fancy solar cells “are formed by placing five layers of material onto  a single sheet of  paper in successive passes. A mask is utilized to form the cell patterns, and  the entire printing process is done in a vacuum chamber” (Singh).  Fabric and paper substrates weigh less than the glass and other heavy backing materials that are typically used, and researchers think that they’re well on the way to developing scalable cells for use in photovoltaic arrays.

So here’s what I’ll say: the day my office printer can power itself by printing out solar cells is the day I will let go of these negative emotions and learn to forgive.

Click  here to see the technology in action (via Inhabitat).

WU XING:

I have filed MIT’s solar cells under water (because of the gentle process) and wood (because they’re flexible and can be printed on paper). And also, privately, under awesome.

Cited:

Singh, Timon. “MIT Unveils Flexible Solar Cells Printed on Paper.” Inhabitat.com 07/11/11. Accessed 07/12/11. URL.

So given these conditions, it will come as no surprise that researchers led by Peter McGrail out of the Pacific Northwest National Laboratory have been working a new porous nanomaterial that improves an existing process used for refrigeration and air conditioning called adsorption chilling.

Image courtesy colmaccoil.com

All refrigerators and air conditioners make the environment cooler by creating phase changes in a refrigerant so that the chemical absorbs heat.  Most familiar air conditioners use electrically driven compressors to mechanically compress the vaporized refrigerant, whereas adsorption chillers use heat to condense the refrigerant. Evaporated refrigerant “adheres to a surface of a solid, such as silica gel. The silica gel can hold a large amount of water in a small space—it essentially acts as a sponge for the water vapor. When the gel is heated, it releases the water molecules into a chamber. As the concentration of water vapor in the chamber increases, the pressure rises until the water condenses” (Bullis). When that happens, heat is absorbed out of the environment and the newly cooled people rejoice!

Image courtesy emissionless.com

Historically, bulky adsorption chillers have been more expensive and far less efficient to operate than chillers that use electrical compressors.  The flip side is that they are cheap to operate and, if you’re an industrial facility or power plant manager who has massive quantities of waste heat lying around, you can practically run them for free. That’s right people: absolutamente GRATIS.

The new material will make it easier to cool smaller buildings with solar water heaters or waste heat from generators by shrinking the hulking adsorption machines by 75% in size and cutting associated costs in half (Bullis).  Size and cost reductions could make adsorption chillers competitive with compressor driven chillers.

The researchers’ nanomaterial consists of “nanoscopic structures that self-assemble into complex three-dimensional shapes. It’s more porous than silica gel, with a larger surface area for water molecules to cling to. As a result, it can trap three to four times more water, by weight, than silica gel, which helps reduce the size of the chiller” (Bullis). The other interesting thing about the material is that it forms weak bonds with water molecules.  This is a good thing because it means less heat is required to free the molecules (or other refrigerants), making the process of adsorbing and desorbing water 50-100 times faster.

While the nanomaterial definitely makes adsorption chilling more attractive, it’s tricky to match the demand for cooling with the production of heat. For example, if you needed to run the chiller when the sun had set because you lived somewhere humid, you might need a heat storage system (and those can be expensive). Still, anytime things get more efficient a little fairy creature gets some wings!

WU XING:

Cited:

Bullis, Kevin. “Using Heat to Cool Buildings.” Technology Review Online. 03/30/11. Accessed 06/29/11. URL.

Image courtesy ursulinesmsj.org

But since there’s no cake, I’m going to write about a new metal panel product coated with, you guessed it: titanium dioxide.  Bonding this chemical to various materials is a growing trend in green building (read about ceramic tiles coated with TiO₂ here) because it’s thought to break down organic matter, SOx (sulphur oxides), and NOx (nitrogen oxides) – the primary component of smog.

Image courtesy ecoclean.com

Alcoa Architectural products has developed a process of applying a titanium dioxide coating called “EcoClean” (the green product naming equivalent of SuperAwesomeAmazingPerfectSauce) to the pre-painted aluminum surface of their Reynobond aluminum panels. As a consequence of the TiO₂ coating, the panels are self-cleaning and break down everything from bird droppings to harmful pollutants.

Image courtesy ecoclean.com

The panels actively remove pollutants from the air in the presence of water and sunlight.  Free radicals generated by the titanium dioxide oxidize the NOx molecules and render them harmless.  Rain washes all said harmless dirt and crud right off the panels, meaning lower maintenance costs for owners and a cleaner image for the building over time (architect is happy! yay!).

Image courtesy ecoclean.com

According to the product literature, installing TiO₂ coated panels “on your building can have approximately enough cleansing power to offset the smog created by the pollution output of four cars every day, which is the approximate air cleansing power of 80 trees every day” (Source: Ecoclean.com).

WU XING:

I am filing this under metal because of the aluminum panels and water because it’s a necessary ingredient for the process to work.