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Coatings De-Ice, Defoul Subs, Jets in Operation

Thursday, November 18, 2010

A Connecticut technology start-up has patented a multilayer composite polymer coating system that can de-ice aircraft in flight and defoul periscope head windows in service.

The technology is an extension of a similar defouling coating system patented by the same company in 2008 for ship hulls immersed in seawater.

The Aircraft Deicing & Periscope Defouling technology, by Smart Coating Systems of Groton, CT, purportedly removes aircraft ice in flight and cleans off fouling from a periscope head window.

The concept for this system (US Patent 7,807,251) and the one for ship antifouling (US Patent 7,390,560) employs specially designed coating arrays that release a fouled layer via triggers of directed heat input from electrical, acoustic or microwave energy.

Aircraft, Periscope Applications

According to the patent description, the new coating array technology has been demonstrated for applications in aircraft ice removal in-situ and for submarine periscope head windows, to remove fouling and provide enhanced optical features.

The coating arrays are comprised of two layers with an adhesive interface between them. The first layer separates from the second layer upon application of energy to the interface, which has sufficient bond strength for flight conditions, according to the patent.

“The final coating array is smooth without unacceptable increase in drag, or weight, easily strippable, and does not alter the physical properties of the rotor surface,” according to the patent description.

“With renewable layers, cleaning or repairing of layers should not be necessary. If required, the array can be recessed (1-2 mm) into the surface to eliminate drag. The coating array can replace the blade top coat or act as an overcoat.”

In the submarine application, “the number of layers in the array, layer lifetime, and thickness are chosen to provide appropriate properties and period of service (e.g., months/layer) in the operational environment. The layer interface chemistry is designed to bond satisfactorily and de-bond at selected electrical energy or heat input obtained from the submarine service system.”

The system purportedly offers less fouling, better optical quality and less degradation of water shedding without cleaning or on-board recoating.

Applications include fixed-wing and rotor aircraft de-icing, ship antifouling, corrosion removal, and chemical biological warfare agent removal, the company says. The system is designed for application to many substrates, including ships, vehicles, clothing, windows and walls.

Ship Antifouling

The previously patented coating system is designed for defouling a substrate, such as a ship hull, immersed in water or seawater for long periods of time.

That system comprises a conductive layer, an antifouling layer, and a means for providing an energy pulse to the conductive layer, according to the patent. The conductive layer comprises polymers, such as carbon-filled polyethylene, which are electrically conductive. The antifouling layer comprises polymers, such as polydimethylsiloxane, which have a low surface free energy.

As with the aircraft de-icing technology, the layers of the antifouling system are designed to separate when the conductive layer is exposed to a pulse of electrical, acoustic or microwave energy or combinations thereof.

Other Applications

The technology also has potential applications for roads and bridges, and the company is seeking investments to fund those applications, said Dr. Morton L. Wallach, president of Smart Coatings Systems. The company is currently setting up small-scale manufacturing for the antifouling coating, he said.
  
Smart Coating Systems is a spinoff of PEL Associates (http://www.pelassociates.com ), which provides new technology and systems engineering for industrial, marine, defense, and homeland security requirements. Activities focus on advanced materials and processing, and new physical and chemical systems. PEL has served over 200 clients, several Connecticut companies and government agencies DOT, DARPA, NAVAIR, and ONR.