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ecoSolv Technologies Inc.
consultation & implementation
unique products & technologies
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Liquid Glass - Nano Surface Treatment
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the future of surface protection ... today!
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Cleanroom Report
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June 2009: Article by Clean Technology – The European Journal of Contamination Control
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Silicon Dioxide Nano Layering Tehcnology (SiO² NLT) may be new to the UK, but soon this
technology will be ubiquitous. This may appear to be glib marketing spin, but the technology
offers stunning performance in a wide range of environments, not the least in healthcare,
food production, and cleanroom facilities.
SiO² NLT has evolved from the manipulation of the sol-gel process – a wet chemical technique
(chemical solution deposition) used widely in the fields of materials science and ceramic
engineering. The process has bee known for more than 60 years, but recent refinements of
it by Nanopool have led to startling innovations. In essence, Nanopool uses the process
to create “liquid glass”, or “glass in a bottle”. The notion of liquid glass is in itself
quite exceptional, but this is only the start of the story.
Via this adapted sol-gel process, molecules of SiO² (pure quartz glass) are isolated and
held within a solvent of either water or ethanol. This “solution” can them be wiped or
sprayed onto almost any surface. The water-based solution is designed for use on absorbent
surfaces such as stone, wood and fabrics. The ethanol-based solutions are suitable for
metal, glass, plastic and painted surfaces.
When applied to a surface, the coating forms a layer of pure glass, which is approximately
100 nanometers thick – 500 times thinner than a human hair. Significantly, there are no
resins or bonding agents within the solution. The bottle or wipe contains only water or
ethanol and molecules of SiO². Quantum forces (Van der Waals force) enable the SiO² layer
to polymerize very rapidly. The dominant force is polymerization, closely followed by
adhesion to the substrate. Hard surfaces, such as wash basins, tabletops, or telephones
can be subjected to loading within 60 seconds of being treated.
The SiO² layer has numerous attributes. With specific reference to clean or hygienic
environments, it is felt that the coatings offer significant benefits. Most significantly,
the whole of a cleanroom can be coated with a film of invisible, super durable and completely hygienic glass.
In some instances, such as when walls, floors and ceilings are coated, the coatings offer
phophylactic and easy cleaning benefits. In other instances the coatings offer enhancements
to certain systems, a perfect example being filtration of water and purification systems.
Ultra fine filters can now be coated with SiO²; this results in greater efficiency as well
as the possibility to clean and reuse the filters. Nozzles and taps can be coated to
prevent the formation of bio-films – a significant issue for organizations that supply
drink dispensing units and water coolers.
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The key attributes of the coatings are;
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Super phobic – bother oleophobic and hydrophobic, thus they reject soiling agents (oil/water/etc)
Flexible – the high level of flexibility (200% elasticity) allows for treatment of items such as endoscopes, fabrics, and conveyor belts
Highly durable – the coatings will withstand tens of thousands of cleaning cycles
Heat tolerant – the coatings can be subjected to temperatures from -150°C to + 450°C
Antimicrobial – all of the coatings are highly cationic and therefore biostatic
Antibacterial – adding triclosan to the matrix can create coatings that kill bacteria in accordance with ASTMe 2180 parameters
Easy clean – all coated surfaces are exceptionally easy to clean as soiling agents cannot bind to the surface; in most instances surfaces can be cleaned with water alone
Inert – the coatings are inert and physiologically harmless
Food safe – the coatings are certified as food safe and can be used in food preparation areas
Acid and alkali resistant – Ph0.5 to Ph12.5
Breathable at the molecular level – highly significant when coating stone, wood or fabrics
Undetectable by human senses – the coatings are invisible and too thin to discern through touch
Free of nanoparticles – the coatings are nanoscale but do not contain any discrete or potentially harmful engineered nanoparticles
Easy to apply – large areas such as floors, walls and windows can be coated in minutes; no special equipment needed
Environmentally friendly – winner of the Green Apple environmental award and the Baden-Wurttemberg environmental protection prize
Low cost – this is a low cost technology; costs to cover 1 sq/ft range from $0.13 to $0.63
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Several cleanroom applications;
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Applications within the healthcare and food production environments are well advanced both
in Germany and the UK. This technology is one of those chosen for the NHS Smart award in 2008/9
– a project directed at rewarding and promoting new technologies that can reduce the incidence
of helathcare associated infections (HCAIs).
All the coatings are tested by leading testing agencies. In addition, clients have conducted
independent tests to evaluate the performance of the technology.
For example, a dairy company carried out a trial in Austria in 2008 in one of its food
manufacturing/processing facilities. The areas within a cleanroom for cheese packaging
were coated with SiO². Key areas of the plant were also coated with SiO². These surfaces
included walls, floors, work surfaces and packaging machines. The trial was conducted
over a seven month period. During the test period all coated surfaces were cleaned with
water alone at 40°C.
The results showed that the SiO² coated surfaces were cleaner than the control surfaces,
which were cleaned with a chlorinated agent.
The coating was still in place after 7 months. The bacterial counts on the coated surfaces
for the month test period were:
Coliform: 0
Yeast, Mold: less than 1
The report characterized these findings as “very satisfactory”.
Almost identical results were gained from trials conducted in a meat processing plant
and at Spar food processing plants. The ASTMe 2180 test, conducted by the Fresenius
Institute, also confirms that the SiO² coatings offer “strong, significant bactericide/fungicide
effects against Escherichia coli, Staphylococcus aureus and Salmonella enteritidis”.*
It should be stressed that coated surfaces can be cleaned with cleaning agent, as these
agents will not affect the coating.
The Sio2 coatings will soon become ubiquitous, as domestic variants of this technology
are already available in the retail market. The automotive market is embracing the
technology for coating fabrics, windscreens, painted surfaces and alloy wheels. Marine
coatings, including anti-fouling, will soon become available and certain stores within
the UK have already have their washrooms and food prep areas coated with the technology.
Almost all surfaces can be coated but the SiO² will not bond efficiently to Teflon or
other non-stick coatings. Additionally, all surfaces must be completely clean prior to
application as a fingerprint can be 100 times thicker than the coating.
The only action that will remove the coating is extreme heat/cold, abrasion, strong
alkali or etching acid. The coating will not corrupt or decay.
If the coating is subjected to a great deal of abrasion then it will last for a shorter
period of time. The domestic grade of coating will last for approximately one year on a
wash basin that is subjected to normal use. The professional grade will last for
approximately two years. The professional grade coatings are slightly thicker (150nm).
There are specific coatings for wood, fabric, stone, glass and ceramic, metal and plastic.
The molecules within the coating are oriented towards the general valence of the
substrates on which they will sit.
Nanopool has created more than 30 variants of the SiO² coatings. Some of the these
are highly specialized but most surfaces can be coated with the standard products.
Surfaces can also be recoated in a very straightforward manner; simply clean the
surface and apply.
At the micro level the coating is slippery, but at the macro level it is not. In
certain instances, for example shower rooms, the treated surface is less slippery
due to the prevention of a bio film.
SiO² technology is exceptional and will be of enormous significance to the cleanroom
industry but, as is often the case, it needs to be seen to be believed.
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