Nanotechnology in coatings Dr. Peter VENTURINI, Assistant Professor Helios Domžale, d.d. Research and Development

one of the largest producers of paint, lacquers and synthetic resins in Central Europe

STRUCTURE OF SALES

INCREASE OF SALES

World paint market 85,7 billion USD. Coatings with nanomaterials around 1 billion USD. Nanoposts.com 2007

Challenges in the coatings market Customers expectations Eco-efficiency and sustainability New scientific discoveries INNOVATION, CHANGE (Water-borne systems!) Customers ecpect more from the coating than protect and beautyfy a surface, Higher performance products, easier to use , Together with legislators and regulators, Customers increasingly expect a greater level eco efficiency of sustainability of products and the way they are producedin the production. Industry has to look to alternatives to petrochemical raw materials, reduce the carbon footprint and is facing a lot of regulatory attention connectet to VOC limits and REACH scientific discoveries and fast development of material sciance is setting new targets and possibitities

History of Nanomaterials Lycrugus cup with diffused light Lycrugus cup with focused light Lycurgus chalice 4th Century A.D. Appears green in reflected light and red if light is directed through it (70 nm particles of silver and gold in the glass)

Expectations for Nanotechnology in coatings Scratch resistance Abrasion resistance Mechanical properties UV-Protection Antimicrobial (Self-cleaning) (Water repellence) Conductivity / Antistatic IR-Absorption / IR-Reflection Fluorescence Gas Barrier Flame retardency Magnetic properties Carrier …… Source: IRL

Nanomaterials in coatings TiO2 Al2O3 SiO2 ZnO Fe2O3 CeO2 CuO ATO, ITO Ag ZrO2 etc. ZnO (antimonijev kositrov (tin) oksid, indijev kositrov oksid) TRANSPARENT! Scratch resistance, UV Protection, Antimicrobial

Synthesis of nanomaterials

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Titanium dioxide (TiO2): micronized – white pigment Paints, plastics, paper cosmetics

Photocatalytic effect nano TiO2 ANATASE Photocatalytic effect RUTILE UV-protection

TiO2 Nano rutile TiO2 transparent formulation for wood UV protection With nano rutile TiO2 cotrol

ZnO for UV protection

Photocatalytic activity of TiO2 ANATASE

without TiO2 with TiO2 thin film water contact angles of the surfaces before and after titania film deposition upon day-light illumination

Nanoadditives to improve Scratch Resistance

After reflow efect After TA abrasion test without nano SiO2

Inorganic nanoparticles are difficult to stabilize in dispersion and in the resin. Compatibility problems during processing: agglomeration, turbidity, increased viscosity Limitating scope of applicability

Coated metal oxides (example from flame synthesis) TiO2 SiO2

Nanoparticle functionalization Gerhard Jonschker et al , Merck KGaA, M. Steinbücher et al. Helios John Texter et al . 2009

Easy to clean surfaces: wetting bahaviour Superhydrofobic surfaces are characterized by low surface energy and the structuring that allows hardly any wettability Hydrofilic surfaces are formed using TiO2 surfaces and require sun light for activation- outside aplication For inside use eg kitchen – oven hydrofobic surfaces are required Inka Henze, Schott AG

Hydrophobic silane surface

Bioinspired materials for self-cleaning and self-healing In practice regenaration of nano structure is a challenge

Mechanical stability regenaration of nano structure is a challenge On awnings finished with Mincor® TX TT, dirt and water simply roll off - without leaving a trace.

Self-healing coatings for corrosion protection Estimated cost of corrosion 300 billion USD per year Prof Braun Beckman Institute University of Illinois at Urbana Mechanical damage Chemical mechanical limitations Cho, S.H., White, S.R. and Braun, P.V., Self-Healing Polymer Coatings, Advanced Materials 21, 645-649 (2009).

Nature is beautiful! nanostructures diffract the light, Butterfly wing: Color without dye is the mystery presented by the luminous blue Morpho butterfly. Its wings are covered with tiny. Unlike chemical pigments, these physical colors never fade. This property also makes them interesting for BASF researchers who are engaged in reproducing the effect with crystalline dispersion coatings. The distance between the crystal layers determines the interference and ultimately the color of the coating. Other applications for films that change their color when stretched are now being evaluated at BASF. nanostructures diffract the light, interference eliminate all the colors except blue