Nanotech in the marine and boat industry.
Nanocoatings find application in military and commercial steel ship hulls and steel, aluminum or fiberglass boat hulls, making them non-susceptible to permanent adhesion of marine fouling organisms such as barnacles, sea-grasses etc. When organisms such as bacteria, barnacles and algae stick to the surfaces of ships it is a costly nuisance. These biofouling organisms result in ships burning 40% more fuel, at an annual cost of more than €5 million for businesses, as well as the incalculable cost to the environment.
Typically, marine coatings are tributyltin self-polishing copolymer paints containing toxic molecules called biocides. They have been the most successful in combating biofouling on ships, but their widespread use has caused severe pollution in the marine ecosystem. Nanocoatings are an entirely non-toxic alternative, which reduces the adhesion strength of marine organisms, facilitating their hydrodynamic removal at high speeds. Since biofouling represents a substantial maintenance expense for hydro-kinetic systems, anti-fouling nanocoatings provide an important solution for these systems and there are now a number of companies producing products. The market will continue to grow, driven by environmental concerns and reducing maintenance costs.
Nanocoatings reduce the flow resistance between the ship’s hull and the water, thereby enabling a significant reduction in fuel consumption and carbon dioxide (CO2) emissions. Desirable functional properties for the marine industry afforded by nanomaterial water-based, anti-foul coatings include:
• super hydrophobicity (less fuel consumption)
• increase durability
• water repellency
• UV-resistant
• fungus/algae/bacteria resistant
• thermally insulating
• elastomeric
• anti-sticking and -corrosive (up to 1000 – 4000 hours of salt spray).
• high resistance to weathering (UV, fungus, water, dirt, etc.) and any blistering over standard marine coatings.
Areas in marine coatings that nanocoatings will impact include:
• Cargo holds: Abrasion resistance
• Cargo tanks: Chemical resistance
• Underwater hull: Fouling control
• Decks: Hard wearing, impact and chemical resistance
• Ballast tanks: Corrosion resistance.
Biofouling
Fouling organisms have traditionally been controlled through the application of antifouling paints that release biocides. Regulations now require that antifouling paints must not cause significant adverse effects on the environment. Nanomaterials allow for environmentally benign coatings. Biofouling can be minimized by reducing bio-adhesion via nanomaterials. Non-stick nanocoatings prevent adhesion of marine life to ships hulls.
Corrosion
Carbon nanotubes have been incorporated into marine coatings for anti-corrosion. These coatings allow for Improved integrity of barrier films due to lower pigment loading and CNT reinforcement. They also display improved improved durability and modulus understress and impact and abrasion resistance. Graphene is also under investigation for application in protective marine coatings as an environmentally friendly alternative to hexavalent chromium.
Fuel savings
Nanocoatings reduce the flow resistance between the ship’s hull and the water, thereby enabling a significant reduction in fuel consumption and carbon dioxide (CO2) emissions. The increase in frictional drag caused by the development of fouling on hulls of ships can reduce speed in excess of 10% (Townsin, 2003). A vessel with a fouled hull burns 40% more fuel which has an impact on fuel costs and additional greenhouse gas production (estimated to be 20 million tonnes per annum).
Chemical resistance
Nanocoatings are under development for marine applications that are mechanically and chemically resistant against sand, salts, enzymes, and bio-compounds produced by marine life. Nanocoatings can restore original color, extreme gloss, surface hardness and UV resistance back into oxidized clear coatings on marine vessels. Nanostructured cemented carbide coatings are used on US Navy ships for their increased durability.
Q
Who are the companies with activities in nanotechnology for marine coatings?
A
There are a number of companies produced nanotech enabled marine coatings including Advanced Marine Coatings (www.amcoat.no), Inframat Corporation’s (www.inframat.com), NanoCover A/S (www.nanocover.dk), Nanogate Technologies GmbH, Nanovere Technologies, Inc. (www.nanovere.com), Diamon-Fusion International, Inc. (www.diamonfusion.com), PURETi (www.pureti.com) and Reactive Surfaces (www.reactivesurfaces.com).
Q
What are the prospects for nanotechnology in the construction industry?
A
Nanostructured materials are allowing companies to develop the next generation of protective coatings for marine applications. According to Battelle, the global marine coatings market in 2012 was worth $4.7 billion, and companies producing superhydrophobic nanocoatings are either already involved or diversifying into marine coatings.
