Why is StoLotusan Color better than a standard masonry paint?
Thanks to the Lotus-Effect®, water and dirt cannot grip the surface of the wall. Water simply rolls off, carrying any loose dirt that has accumulated on the surface with it. The wall remains clean and dry, effectively removing the habitat required for the spread of micro-organisms such as algae and fungus.
Doesn't rain wash the dirt off any surface?
No. A standard masonry paint allows the rainwater to sit on the surface, leaving it damp. Dirt accumulates and combines with the water, damaging the appearance and creating a fertile habitat for micro-organisms such as algae and fungus.
Even after several years, StoLotusan Color shows significantly lower soiling than other facade paints. Practical tests conducted by respected building institutes have shown that StoLotusan Color can provide a reduction in soiling of up to 80%.
Is StoLotusan Color expensive?
StoLotusan Color is a little more expensive than a standard masonry paint, but in the long-term it is extremely cost-effective and likely to even save you money:
- Maintenance cycles are up to 3 times longer than a typical facade paint.
- Reduced maintenance means reduced refurbishment costs for substrate treatments, replacement paint, scaffolding, etc.
Is StoLotusan Color a "never-paint-again" product?
Claims of never needing to paint again are misleading at best. All painted substrates will require maintenance at some point.
StoLotusan Color requires less regular maintenance than a standard facade paint, and maintains its looks for longer too, but we do not claim you will never need to paint again.
What are the necessary conditions for the Lotus-Effect® to work?
The two characteristics required for the Lotus-Effect® are a microstructure that creates a contact angle of 140° or greater, plus a hydrophobic material. Together, a superhydrophobic surface is created.
StoLotusan Color provides both of the characteristics required for the Lotus-Effect®.
What does "superhydrophobic" mean?
Superhydrophobic relates to the contact angle between a water droplet and the surface. If a surface is superhydrophobic, water cannot maintain surface contact and rolls (rather than flows) across it. A contact angle of 140° or greater is required for this effect to be seen.
What does the contact angle of 140° do?
When a droplet of rain water falls onto the surface painted in StoLotusan, the droplet is only able to touch the surface at a few contact points. Unable to grip the surface, the droplet forms into a bead and simply rolls off at the slightest incline.
This reduction in contact points is caused by the 140° contact angle between the microstructure and the droplet. This phenomena provides us with the basis of the Lotus-Effect®.
What does "biomimicry" mean?
Biomimicry relates to reproducing natural phenomena in a human-designed product. Biomimicry is also known as "biomimetics".
Other well-known applications of biomimicry include Velcro™ (inspired by the hooked burrs of the burdock plant) and fibre-optic cables (inspired by the ability of the deep-sea sponge Euplectella to produce strong structures from fragile materials).
Are Lotus-Effect® coatings and the surface of the lotus leaf identical?
Biomimicry does not mean creating an identical copy of the natural phenomenon, but learning from and adapting it for application in commercial products. The lotus leaf uses waxes and self-organising crystals to produce its remarkable surface properties, but facade coatings must meet other requirements as well.
It took four years for Sto to develop StoLotusan from the initial concept. Firstly, StoLotusan needed to fulfil the demands placed upon modern facade coatings, requiring consistent raw materials. These raw materials had to be selected in order to form the required microstructure and water-repellent material.
Does StoLotusan Color use nanotechnology?
No. The facade paint StoLotusan Color does not contain any nanoscaled particles.
Although the natural effect of the Lotus plant is based on a combination of micro and macro structures, the Lotus-Effect® was successfully transferred to the facade paint using only micro-structured components.
StoLotusan Color is not a health-endangering preparation within the meaning of the EC directives 67/548/EEC or 1999/45/EC.
StoLotusan Color has a microscopic undulating surface, producing the contact angle required for the superhydrophobic surface.
Can StoLotusan Color be tinted?
Yes. StoLotusan Color can be tinted in 618 colours, tested for long-term colour stability. When referring to the StoColor chart, all colours marked with the Ο symbol are available for StoLotusan Color.
Is StoLotusan Color a silicone resin paint?
StoLotusan Color is based on silicone resin technology, although the naturally hydrophobic surface has been greatly increased. The surface microstructure has also been highly modified leading to the extreme reduction of the contact area for dirt and water.
Standard silicone resin paints (such as StoSilco Color) provide higher water resistance and a lower tendency to soiling than a typical masonry paint, but only StoLotusan Color features the superhydrophobic microstructure required to prevent water and dirt from clinging to the surface.
Other silicone resin paints are also microstructured. Isn't StoLotusan Color just one of many?
All facade paints open to diffusion are micro-structured, but the binder content is so low that the fillers and pigments are not fully bedded. Other silicone resin products do not feature the integral microstructure that reduces the surface contact between the coating and water.
What is the function of the film conservation in StoLotusan Color?
StoLotusan Color requires approx. 1 month after application to develop the contact angle of 140°. After approx. 6 months the contact angle increases to 150". During this build-up phase, a special film conservation protects against attack by micro-organisms.
Over time the film conservation reduces in effectiveness, but as soon as the contact angle has developed, the Lotus-Effect® will take effect, providing the best possible protection against micro-organisms.
Areas of Use
Is it possible to apply StoLotusan Color onto an external wall insulation system?
Yes. StoLotusan Color is ideally suited for use on an external wall insulation system with a render finish.
Can different render textures or grain sizes affect the Lotus-Effect®?
Provided the whole surface of the grain or texture is coated with StoLotusan Color, there should be no reduction in the Lotus-Effect®. If the whole surface has not been painted correctly then small pockets in the render may trap water, preventing it from running off the wall.
StoLotusan Color should not be diluted by more than 10% or the necessary surface characteristics cannot be formed. Two coats should be applied in order to ensure complete coverage.
Is it possible to apply StoLotusan Color onto concrete or reinforced concrete surfaces?
Yes. StoLotusan Color may be applied onto concrete and reinforced concrete. Please adhere the guidelines found in the technical data sheet in order to ensure a successful application.
Is it possible to apply StoLotusan Color onto metal or timber?
No. StoLotusan Color is not suitable for metal or timber substrates.
How does StoLotusan Color react to alkali substrates?
If the substrate is dry and primed with Sto-HydroGrund, alkalinity does not affect the film conservation agent.
How does StoLotusan Color react to salts (nitrate, sulphate)?
Salts, in the same way as detergents, remove the surface tension and prevent the effectiveness of the Lotus-Effect®. Washing the salt away will usually cause the Lotus-Effect® to return.
High concentrations of salt can permanently damage the Lotus-Effect®.
Is it possible to use StoLotusan Color indoors?
In principle, StoLotusan Color can be used indoors, but it is not recommended.
Without a steady flow of rain water to clean the surface, dirt will continue to accumulate on the wall. Other methods of cleaning indoor surfaces, such as scrubbing, cleaning agents and high-pressure hoses, will all damage the Lotus-Effect®.
Can StoLotusan Color be used underwater (e.g. as a self-cleaning surface in water basins)?
No. The Lotus-Effect® only works on the border between the coating and the air.
Is it possible to use StoLotusan Color as an anti-graffiti coating?
No. The lacquers used in graffiti sprays are extremely aggressive, usually containing solvents that can damage the microstructure required for the Lotus-Effect®.
What happens to StoLotusan Color after a long period without rain, or in areas where rain cannot reach (e.g. an overhanging roof)?
In long, dry periods or areas permanently sheltered from the rain, there will be an accumulation of dirt particles on the surface over time. The Lotus-Effect® ensures they do not attach to the facade. For exposed areas, the dirt will wash off when it eventually rains.
If necessary, it is possible to wash StoLotusan with a low-pressure hose. Do not use a high-pressure hose or cleaning agents, as these can damage the Lotus-Effect®.
Can aggressive urban or agricultural pollutants impair the Lotus-Effect®?
Airborne pollutants do not damage the Lotus-Effect® because they do not come into direct contact with the StoLotusan coating. Such a contact reaction could only occur when mixed with rainwater, but as water is also unable to grip the surface and simply runs off, surface contact should not be a problem.
Oily pollutants such as diesel can adhere to the surface and damage the Lotus-Effect®.
Substrate Preparation & Overcoating
What priming, pre-cleaning or other substrate preparations are necessary to apply StoLotusan Color?
As with all paint coatings, the substrate must be clean and dry before application.
A substrate preparation coat of the solvent-free, hydrophobic, consolidating primer Sto-HydroGrund is required for the Lotus-Effect® to function correctly.
The substrate must be capable of accepting the paint finish. For this reason, suitable suction is essential. Please refer to the technical data sheet for more details.
Why is it necessary to use Sto-HydroGrund with StoLotusan Color?
Emulsifiers can have a negative effect on the characteristics of StoLotusan Color. These can migrate to the surface and can have a negative influence on the Lotus-Effect®.
Sto-HydroGrund has been thoroughly tested and approved for use with StoLotusan Color so as to not damage the Lotus-Effect®.
Is it possible to overpaint StoLotusan Color with another paint, or does the Lotus-Effect® reduce the bond?
It is possible to overpaint StoLotusan Color with other facade paints without impeding the bond.
Note, however, that overpainting StoLotusan Color with another facade paint removes the special contact properties and stops the the Lotus-Effect® from functioning.
Is StoLotusan Color suitable as a substrate for decorative washes or other transparent coatings?
Under no circumstances should StoLotusan Color be overcoated with a transparent coating, as this damages the microstructure required for the Lotus-Effect®.
Branding, Patents & Rights
Which products are available with the Lotus-Effect®?
Patents for the Lotus-Effect® have been given to a number of industries, including glass, automotive and roof tiling. StoLotusan render and StoLotusan Color paint are the only facade coatings with the Lotus-Effect® on the market.
Has the Lotus-Effect® been patented?
Yes. The self-cleaning surface with nature as a model was registered for patent in 1999. The European patent was granted No. 0772514 on 13th December 1998. The patent owner is Prof. Dr. Wilhelm Barthlott.
What further protection rights exist together with the Lotus-Effect®?
Prof. Dr. Wilhelm Barthlott has ensured that the Lotus-Effect® brand is internationally protected. The StoLotusan brand is internationally registered.
Are there any imitators to StoLotusan Color?
There are several imitators, some of which appear with similar claims, descriptions and images.
For this reason we point specifically to our technical data sheets and specifications to the contact angle of 140° and the extremely low water absorption after 6 days of just 1.1%. These values cannot be attained by any other paint.
Customers are advised to make a comparison of these values with proof from the competitor.