Nanotechnology as the source of new cleanliness
by Thomas Edelmann
Mar 12, 2015

“Clean is all very good. Clean is bright and nice. Dirt is ugly and elsewhere,” or so the opening lines of Christian Enzensberger’s poetic text, published in 1968 as “Smut: An Anatomy of Dirt”. When, back in the 1920s, the pioneers of Modernism fought to champion a new type of architecture, they did so among other things because they wanted urban planning to deliver on health and hygiene. The call for more light, air and sun spelled turning one’s back on downtown tenement blocks with countless inner courtyards and dark rooms, and no bathrooms or toilets. Only in the post-1945 period did this standard slowly become the norm.
Last year, at the Venice Architecture Biennial, in his exhibition of “Fundamentals” Rem Koolhaas highlighted the elements of modern construction. Not infrequently, the changes to buildings, their greater efficiency and streamlined manufacture have gone hand in hand with a deterioration in their design. Koolhaas also dedicated a room to the toilet. He showed examples from the days of the Chariot latrines as were used in the Caracalla Baths in Rome, through studies by toilet researcher Alexander Kira conducted in the 1970s, to contemporary Japanese washlets with music and fragrances and sensor controlled toilet lid. Today, the toilet is a “fundamental zone of interaction between people and architecture at the most intimate of levels,” we read in the Biennal catalog. Architect Bernard Rudofsky went on record in the 1980s that toilets are “much too delicate a matter to be left to the likes of tradesmen or gastroenterologists.”

High-tech coatings combat dirt

Not only has time flushed by since the 1960s and 1980s, but the approach taken to the toilet as a topic of design now rests on different assumptions. One of them is: hygiene at the flick of a wrist. The other: sustainable use of resources. In homes, many have declared war on omnipresent bacteria and viruses, deploying an array of detergents that are as aggressive as possible to do the job. The idea is that the more detergents in battle, the better the result, something the manufacturers of the chemicals love of course. Precisely in and around toilets a veritable cult of the germ-free environment has arisen. And cleaning processes are meant to be super-fast, not just in homes, but certainly in the contract market. Moreover, the idea is that in order to protect the environment, as few toxic detergents as possible will be used, as when they degrade they have an execrable impact on the quality of water in lakes and rivers, and eventually our groundwater, too.
All makers of sanitary equipment now tend to offer an optional nano-coating for most of their product lines. Duravit calls it “WonderGliss”, developed along with “Nanogate”. At Keramag there’s not just the “KeraClean” coating, but also a pore-free glazing called “KeraTec”. Villeroy und Boch market “CeramicPlus” as an added extra. There are not just coatings to facilitate cleaning, but ones that are antibacterial; in fact, both are at times combined. Toto washlets can optionally come with “Actilight” technology, a combination of coating, flush and decomposition of dirt particles using UV light from the toilet’s lid.

Nature as the role model

Most of these refined surfaces take their cue from self-cleansing lotus leaves and are as good as the standard today. The new coatings seem very smooth at first sight, and only if viewed through an electron microscope will you discern the lines of clefts in their surfaces. Starting back in the 1980s, there was a swift transition from biological research and physical explanation to industrial applications. University research institutes spawned various companies with expertise in the mechanics and manufacturing of such coatings. Moreover, nanotechnology was soon a growth market that was receiving research subsidies throughout the EU. The German Environment Agency has not yet passed definitive judgment on the extremely small particles that can in part overcome biological barriers. We simply know too little about enriching them and about how they interact with other materials.
In nature, self-cleansing surfaces consist of nano- or micro-level crystals made of lipids that arise through self-organization on plants’ cuticles, their outermost protective skin. For restroom applications, the preferred choice are fine-grained, brittle particles of quartz sand or aluminum oxide that are not larger than 20 nanometers in size and are integrated into a plastic-like matrix. The resulting network repels water, dirt and oily substances alike.

Today’s motto: scratchproof and no rim

For WCs to remain in a state of “panta rhei” (“anything flows”), manufacturers are going for a new kind of water supply. High-end contemporary toilets tend to be as free of hollow cavities as possible, as these get in the way of cleaning. While there was a time when a decent flush rim was considered the epitome of elegance, today the better the WC, the less it’s likely to have any rim at all. Toto has offered rimless WCs since as long ago as 2002, European manufacturers such as Ideal Standard or Villeroy und Boch have now started including such models in their lines.
Scientists are still busy researching nano-coatings. Because to date, scouring powders or scratchy sponges swiftly destroy the practical coatings. A British Team at the University College in London, leaded by Ivan Parkin has now developed a scratchproof non-surface – in the lab. It’ll be one or two trade fairs before the idea is in mass production. But what was it Christian Enzensberger said towards the end of his essay: “… take note: clean is powerful, clean is here to stay.”

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From the stony beginnings to modernism: A chariot latrine and a contemporary WC at the exhibition “Fundamentals”. Photo © Francesco Galli, Courtesy la Biennale di Venezia
With the enhanced ceramic glaze “CeramicPlus” by Villeroy & Boch water, dirt and oil fluids should roll off easily and no aggressive cleansers are needed further more. Photo © Villeroy & Boch
After using the toilet, the toilet lid of „Neorest AC Washlet“ by Toto closes automatically. The seat is irradiated by UV light for one hour for cleaning. Photo © Toto
The model „Darling New“ should be easy to clean with its rimless flush technology. Photo © Duravit
Without a rim, there are less germs –with models by Villeroy & Boch only up to three liters are used per flush.
Photo © Villeroy & Boch
With the antibacterial glaze “AntiBac” by Villeroy & Boch there should be almost no germs. Photo © Villeroy & Boch
On surfaces like “CeramicPlus” by Villeroy & Boch, water and dirt particles form drops and roll off the ceramic easily. Photo © Villeroy & Boch
The rimless WC technology “DirectFlush” by Villeroy & Boch prevents, that water splashes over.
Photo © Villeroy & Boch