FAQ - frequently asked questions
Do the photocatalysis require a direct light exposure?
Not Necessarily. The photocatalytic process takes place not only with direct light exposure but also with reflected lights, regular fluorescent lights if there are some portion of UV lights. The natural sunlight, which is free, is more desirable!
Is photocatalytic effect also occurring with overclouded sky?
Yes. Generally, UV light is still available even in the overclouded sky. The UV can pass through the clouds with reduced intensity, but still photocatalysis can take place.
What portion (% of total area) of compartment should be coated, to assure satisfactory self-cleaning effect of atmosphere in a fish processing plant?
It is common that self-cleaning effect does not mean de-odorization or destruction of organics. Desired function should be clarified first because different coating solution has to be chosen.
This subject requires an individual approach. The final effect depends on total sprayed (coated) surface and intensity of light exposure. Generally it depends on the initial concentration of the target material and other impurities. Basing on similar cases for animal growing farms, because of excessive odor in such compartments, it is recommended to spray 100% of interior surfaces.
Is the self-cleaning also effective during the night?
Actually hydrophilicity is more correct. Yes, hydrophilicity remains active in the darkness because the portion of energy due to daylight exposure is acting through many hours afterwards.
Is the self cleaning process possible also without a rain?
Yes, it is. The process might occur by oxygen and moisture from the environment. A super-hydrophylic TiO2 coating is utilizing the surrounding oxygen and moisture for chemical reactions.
The walls and bottom of swimming pool treated with TiO2, are they self-cleaning and remove bacteria? Maybe, they clean up the water itself?
We do not call this case “self-cleaning”. It is better to say “water purifying”.
UV light does not penetrate into deep water layer. Therefore, the process might take place only at the walls not bottom. But visible light photocatalysts might be used because longer wavelength of light could penetrate into deeper water layer. For swimming pool water cleaning, we suggest you to install photocatalytic water treatment system that Nanopac can design and build upon customer’s request.
The water in TiO2 coated glass, is it self cleaning?
We do not call this case “self-cleaning”. It is better to say “water purifying”.
The positive holes, in particular, are better oxidizers than the chlorine often used as a disinfectant and sterilizer and also better than common oxidizing agents such as hypochlorous acid, hydrogen peroxide, and ozone. Harmful substances adhere to the positive holes and are then completely broken down into carbon dioxide and other harmless compounds. The positive holes also inhibit the growth of bacteria and mold. Consequently, it is possible to have clean, odorless, delicious water by pouring water into vessel and stirring it with a TiO2-coated swizzle stick in direct sunlight or lamp light. The time relationship between the concentration of impurities in the water, the amount of incidental light, and the surface area of the TiO2 film. The stronger the light source and the more vigorous the mixing the less time purification will take.TiO2-coated glass vessels also have a germicidal effect on their contents when exposed to light. When a liquid culture of E-coli bacteria was placed in a glass cup and shaken in fluorescent light for six hours, only 10% of the bacteria died. When exposed to sunlight, over 90% of the E-coli died. Flowers held in a TiO2-coated glass vase will last longer than in a conventional vase because the water dose not decay so easily. TiO2-coated containers also make for good tropical fish tanks, as they help prevent the growth of algae. For more active water purifying system, it is better to install a photocatalytic system rather than just coating TiO2 solution.
An accidental inspiration of compound during a spray application could be harmful to the health?
All spraying operations are to be executed with a facemask to prevent from intaking any compounds. When this happens just follow the direction attached to each product.
A taste of drink, e.g. the juice, in TiO2 coated glass – would not be changed?
NANOPAC never tested this. But some people claims that water tastes better or alcohol tastes better. Do test yourself. However, proper coating solution has to be chosen first prior to coating.
Can the solution be diluted prior to spray-out?
Absolutely not. The special composition must be maintained.
Can the self-cleaning effect be obtained on washroom fittings, tiles, mirrors and walls of shower cabin so, that neither soap remnants nor water drop stains would settle on?
Yes, such effect can be obtained by application of photocatalytic coatings and appropriate light exposure on tiles, mirrors and walls of shower cabins. The more light (UV included), the better effect. However, for fittings material information is critical before coating application.
A kitchen pot having a self-cleaning coating, does it require an additional washing, or simple flushing with water would be sufficient?
Provided, there is sufficient light exposure, an immersion in water or just flushing with water would be satisfactory. However, there may occur some spots requiring cleaning. Shining light will kill the bacteria.
The front wall of building, coated with photocatalytic TiO2, will it show smudges or stains? Can it resist the graffiti?
The smudges are result of dirt being transported by rainwater from the contaminated to some cleaner spots. In urban areas these smudges are usually made of fat dirt of industrial origin. The photocatalytic TiO2 coatings, thanks to their superhydrophilicity and self- cleaning effect, are efficiently fighting such smudges. However, it is important to “liquidate” as much as possible, all potential dirt sources, like any recesses in wall, billboards, etc. They should also be coated with TiO2 and be self-cleaned, too.
The photocatalytic TiO2 coatings are fighting the graffiti to some degree. A final effect depends on kind of wall surface. A complete 100% removal of graffiti by using a water spray is possible only with walls of the aluminium or stainless steel. -> For this purpose, different type of coating solution (not TiO2) has to be used.
Can the self-cleaning coatings be applied onto stone monuments, which are dirtied by birds?
Never tested!! Not sure bird’s dirty can be removed or not.
Yes, an excellent application. The old monuments would require however, a thorough cleaning prior to coating.
A kitchen sink covered with self-cleaning coat, would it require other maintenance than just spraying with water?
(The new coating solution for sink bowl is under experiment in Korea. The following answer is based on new solution.)
Most probably it would not. The surface hardness of the coating would be 3-4H. Thus, please do not rub the sink with metal brush. That will peel off the coating surface. The sink will be free from greasy spots, water smudges, fingerprints or other pollutions.
What is the maximum temperature on heaters, heat exchangers, etc. to apply a self-cleaning coating?
NANOPAC has not tried this. But the following answer would be mostly probable. The temperature of coating after application should not exceed 6000C. Do not perform coating when surface is hot.
Is it better to apply the self-cleaning and bactericidal coating upon the tiles prior to or after their setting on floor or walls?
You can coat either before or after. More correct is coating after setting of tiles. In such case are also treated the gaps between tiles and corners between walls and floor. Most of bacteria are gathered in these places. Besides, the recent sanitary regulations recommend rounding up these corners, to prevent collection of bacteria.
At minus temperatures, the car window glass with photocatatytic coating would not accumulate a thin ice film because of superhydrophilicity?
No, because on glass surface will be less water than in case of non-treated glass. Eventually, the drops of freezing rain will also be less troublesome. Experiments are in course.
Can this compound be applied upon yacht canvas, because of high humidity and salt?
Maybe, the hydrophobic preparations would be better?
Certainly, the TiO2 photocatalytic coat will keep the sails in clean condition and will prevent its fading. However, before coating you may find out the appropriateness of the coating solution and the material that is made of canvas.
Can the coated windshield of car be exploited without wipers?
In certain conditions, yes. Especially at heavy rain. However, it depends on the eyesight of the driver.
How to prepare the body or glass of used car prior to putting on a photocatalytic coat?
In case of already built glass pane such as building and car:
1) Clean with water and detergent, and then rinse with water
2) dry completely
3) soak alcohol (ethanol and etc.) into fabric or cloth, and then rub on the surface of glass
4) P&T-100 coating ; spray or sponge soaking-rubbing
The toilet pan and/or seat will be bacteria free permanently?
Bacteria free stays as long as coating lasts. The coating itself can last for longer than 3 years, however, if the coating surface rubbed frequently, it won’t last that long.
Beside of window glass, the coatings can be also applied onto the window frames of aluminum, plastics, wooden?
Yes. However proper type of product to each substrate must be chosen.
Is the anti-bacterial and self-cleaning effect taking place in indoor compartments?
Yes, with some light through the windows, verandas, luxfers. The regular fluorescent light bulb also emits some uv portion. The more incoming light, the better effect is obtained. Of course, an artificial light with UV lamps can be used, too. Such solution can be utilized especially in hospital compartments, where the UV lamps are installed for anti-bacteria purposes. Combining the TiO2 photocatalysis and exposure to UV lamps is bringing excellent results. In the nearest future the new coatings sensitive to visible light, artificial included, will come onto the market. NANOPAC is actually carrying R&D on this subject.
The shirts sprayed with TiO2 - must they be washed, or do they get stained?
Unfotunately yes, however more rarely. Effect of bacteria killing is providing reduction of sweat odor, what allows for prolongation of inter-wash intervals. The fabric will "receive" a wet stain (hydrophilicity) of organic origin and then it starts to degrade it. This will facilitate the future wash. A dirt coming from dust in air or fat expelled by the skin (especially at the collar), will be considerably smaller.
The coat put upon the oil or aquarel pictures, would not be noxious due to its strong hydrophility?
This is never tested and we do not recommend coating on the oil or aquarel pictures !! But printed pictures might be OK. Superhydrophilicity does not cause a moisturing of substrate, in this case a picture. Instead, it ensures a quicker drying of wet spots or even water drops. A droplet “spread” over a large surface has bigger evaporating area and dries more quickly. The more important aspect in this case is assurance for maintaining the colours (photocatalytic TiO2 coatings are excellent means against UV radiation), as well as a clean state: the dust, bacteria, fungus, etc.
In case of a wall painted with the emulsion or acrylic paint and additionally with TiO2 photocatalytic coat, would it self-clean a dirty spot made by a shoe?
A dirty spot made by a shoe accompanies some impact on the surface of the coating. Such impact would destroy the surface in most cases.
Will a dust settle on furniture treated with TiO2 coat?
Yes, but in much smaller degree, because it has a minor anti-static effect too.
The TiO2 on room walls would not bring any noxious side effects to our health?
No, quite the opposite. Living in clean air and clean walls is pleasant and healthy. In a living room the cigarette smoke (and other odors and gases) is currently deactivated and leaves no yellowish shade or smell in the compartment.
The contact of flesh with TiO2 treated fabric is safe? What about intensive oxidation at the surface? Can the titanium molecules penetrate through flesh into blood? (??)
After coating with all kinds of solutions is not harmful anymore. Contacting of flesh with a treated fabric is not dangerous, as well as with P&T 230 solution too. The coating surfaces after suitable application as in the direction are not classified as noxious to the health. However, solvent-based solutions themselves, i.e. before coating are not healthy to human body.
The carpet or upholstery sprayed with TiO2 preparation; will they be free of saprophytes? Will the vacuum cleaning or washing reduce effectiveness of TiO2?
I guess P&T 230 would bother saprophytes. But P&T 230 has not been tested with saprophytes. The vacuum cleaning would not reduce the effect of Nanopac products, while the washing process could reduce the effect of P&T 230. After cleaning, just re-spray it.
The floors covered with carpets or lining, as well as upholstery of furniture in living quarters are the main source of toxins (together with air conditioning). In the dust collected therein, besides of pesticides may be present also carcinogenic polycyclic aromatic hydrocarbons, bacteria, fungus and their spores and saprophytes. All of them except of saprophytes / together with saprophytes will be liquidated by application of appropriate Nanopac product. Dedusting and washing have no effect on effectiveness of nano-preparation.
What is the minimum coated surface to obtain a perceptible effect of air cleaning in living compartment with a big window?
Some of Japanese firms had started to use the flower compositions or artificial trees treated with TiO2 photocatalytic coat to provide air purifying effect in living rooms. Such active surface seems to be too small, however, it works. To achieve spectacular effects in reduction of volatile matters to almost zero level during a few minutes time, a maximum size of surface along with ceiling should be covered with the coat. In most cases it is the whole area in compartment.
Is it possible to apply the preparation to inside of leather shoes, boots, etc. in bactericidal purposes?
Yes, it is possible. One should remember only that bactericidal effect would take place when exposed to appropriate dose of UV radiation. Therefore, shoes should be kept in well-lighted compartments.
Will the self-cleaning take effect on leather articles?
The main purpose of P&T 230 on the leather is deodorization.
However, it has hydrophilicity, thus it could exhibit minor self-cleaning effect.
In subsequent washings of spray treated fabric, will the effectiveness of compound be maintained without fade-out?
Nanopac has not tried such cases. Definitely, it will depend on the quality of the fabrics and how to wash the fabric. I would say the effect of decomposition of bad smells and VOCs would decrease after washings. Repeated washing could gradually remove coated material.
A plaster wall painted and then sprayed over with TiO2 coating, can it be repainted again in the future? Would the wall not “reject” new paintwork taking it for a kind of pollution?
Yes, it could be repainted without any problems. Perhaps more tests are necessary.
What „Healthy effect” can provide a TiO2 coating applied in home or office? For example, with regard to the “sick house syndrome” ?
Examinations of „sick house” problem comprises determination of effect of the building materials, air circulation, paints and glues used in finishing of interior, as well as their influence upon health and comfort of life. It results from the WHO report, that in every one of three examined offices there were discovered almost 300 noxious chemical substances emitted by the building, decoration materials and equipment, including formaldehydes and styrene. The biggest emission intensity was found in new buildings. When adding some bacteria and fungus generated in AC filters due to the over tight window panes, all aspired into lungs of people working inside, then the reasons of subsequent diseases of the aspiration system, allergies, headaches, weakening of immunology condition, skin diseases, permanent fatigue and depressions are evident. These problems can be dealt with by putting a TiO2 coat:
• on the walls, floor and ceiling – to kill the bacteria and fungus thereon, removal of volatile organic compounds(VOCs) and reduction of noxious gases, e.g. from xerocopiers,
• on AC filters – to kill bacteria and fungus cumulating there, and to decompose VOCs, bad smells, and so on.
• on filters of the fresh and clean air – to kill bacteria and fungus, and to decompose VOCs, bad smells, and so on.
• on floor lining and upholstery – to kill bacteria and fungus and to decompose VOCs, bad smells, and so on.
• on furniture – to fight bacteria and viruses and to decompose VOCs, bad smells, and so on.