Smart Materials and Smart Coatings
In cooperation with partners Axcentive have developed state of the art technologies responding to professional markets such as Protective and Transportation Coatings, asking for these value added functionalities, so far used in consumer gadget markets mainly. Now the EXOCOAT technology empowers formulators to address these needs.
- EXOCOAT Superhydrophobic Spheres
- EXOCOAT Organometallic Nanopolymer
- EXOCOAT Photocatalytic Nano-Titanium Oxide
- EXOCOAT Sol-Gel-Technology
EXOCOAT Superhydrophobic Spheres
Superhydrophobicity holds a long promise of rendering coatings into water excluding surfaces, so that water is not able to hold or stick to it. Nature itself invented the so-called ‘Lotus effect’ referring to the lotus leaf which has an extremely water repellent surface. From this surface, water droplets roll off due to the very high contact angle of >140o. With the water rolling off, the surface cleans itself as the water dissolves dirt and soil on its way down. Superhydrophobicity requires a physically structured surface additional to a specific chemical nature of the surface.
We can create a nano morphology from stabilized spheres and by that obtain a superhydrophobic surface. This morphology resembles a comb like structure.
Superhydrophobic coatings based on these spheres can be used in various applications:
- on concrete and wood where they soak in the porous substrate to make it fully water excluding,
- on textile to make water impermeable, yet breathable clothing, or
- on the inside of phones, tablets and so on to protect them from short cuts by water.
EXOCOAT Organometallic nanopolymer
The development of a nanopolymer with both inorganic and organic parts has resulted in a resin that gives inorganic reactive sites, internal reactivity and hardness. Simultaneously the synthetically incorporated organic part provides hydrophobicity and oleophobicity.
This engineered organometallic polymer is developed for:
- Automotive Coatings, to give easy to clean properties on for example body work and rims
- Protective Coatings, for direct to metal application and as easy to clean topcoat
- Coil Coatings, to give easy to clean facades and anti-fingerprint appliances
Moreover as standalone resin in a coating formulation it will form extremely hard and durable hydrophobic finishes.View Brochure
EXOCOAT Photocatalytic Nano-Titanium Oxide
Self-cleaning coatings based on photo catalytic nanotechnology are truly smart as they actively destroy dirt particles with the help of light. The coating is able to create radicals in moist air. These radicals can oxidize dirt to the base elements CO2 and H2O. See also the illustration on this page.
A second property of these coatings is its superhydrophilicity. In below picture it is shown that after photo-oxidation, water may flush down the dirt particles. This is especially efficient for inorganic particles that dissolve easier into water.
Photo oxidation and the rinsing with water do not necessarily have to take place simultaneously, although it is advantageous.
The photo catalytic process can be tuned so that even on cloudy or rainy days the systems is active. In such case there is no need for direct sunlight.View Brochure
Sol-gel-technology has become a powerful technique to come to thin functional layers that can modify the properties of metal, glass and mineral surfaces in many ways. The chemical process is relatively simple: metal alkoxides like silanes, zirconates or titanates are hydrolysed in presence of water (the “sol”) then condensate to form a gel, followed by a curing step to get the final coating.
The physical process is more complex. The nanoparticles of the sol need stabilization and the process from sol to robust coatings depends much on the chemistry used. Some routes lead to agglomeration, coacervation and Ostwald ripening, which damage the homogeneity of the sol.
In the EXOCOAT technology, inorganic and functional organic sol-gel materials give relatively thick layers with hydrophobic and oleophobic effects. This can advantageously be used in for example, windscreen coatings and stain resistant metal coatings.
Another great application of sol-gel-technology is in anti-corrosive paints. In this approach, the sol-gel system chemically converts the top layer of the metal into an inert barrier. With sol gel coatings a nano layer of the metal surface is converted to inert oxides like SiO2, ZrO2 or Al2O3, dependent on the metal alkoxide used, which are resistant to heat, acids and chlorine attack.
Sol-gel systems may be formulated into coating systems using traditional pigments, fillers and additives.View Brochure