Superhydrophobic and oleophobic coating for aluminum heat exchangers based on textured surfaces
Navy SBIR FY2018.1

Sol No.: Navy SBIR FY2018.1
Topic No.: N181-019
Topic Title: Superhydrophobic and oleophobic coating for aluminum heat exchangers based on textured surfaces
Proposal No.: N181-019-0795
Firm: Nano Terra, Inc
737 Concord Avenue
Cambridge, Massachusetts 2138
Contact: Christopher Thompson
Phone: (617) 621-8500
Web Site:
Abstract: Aluminum heat exchangers suffer from reduced performance and increased maintenance due to fouling. Of the coatings currently available for heat exchangers, most are severely fouled when the coating surface comes in contact with oils and dust. A superhydrophobic and oleophobic coating would reduce fouling and make cleaning easier. Nano Terra has developed a coating for aluminum parts, called NT-AL, based on a textured, low energy surface which completely resists wetting by water and oil. The coating is < 30 micrometers thick and so would not interfere with heat transfer. It is erosion resistant and is intimately bonded to the aluminum surface so that the coating will be robust even in high particulate environments. In this program, Nano Terra will refine the NT-AL process for the Navy?Ts heat exchangers and verify the maintained performance, fouling resistance and wear resistance. In parallel, Nano Terra will develop a low-surface energy polymer coating with a textured surface that will provide similar superhydrophobicity and oleophobicity to NT-AL but potentially better erosion resistance and different chemical stability. Finally, Nano Terra will apply the best two of these approaches to heat exchangers and show improved performance in fouling conditions.
Benefits: The breadth of impact had by fouling of materials is difficult to understate. Wherever a product is exposed to natural elements the buildup of undesired material on its surface may have a negative effect on the cosmetic, structural or performance characteristics of the product. This is especially true in the case of heat exchangers, but also applies to innumerable items in industries such as manufacturing, construction, and transportation. Active heat management is a critical consideration in myriad industrial processes, including energy generation, food production and manufacturing. It also appears in residential and transportation sectors in the form of building heating and cooling and automotive engine cooling. According to some estimates, 7.5% of maintenance costs for process plants and up to 0.25% of the GDP of industrialized countries is attributable to performance degradation and cleaning costs associated with heat exchanger fouling. Since a large fraction heat exchangers are made of aluminum (due to its low cost, high stability and good heat transfer properties) passive fouling-resistant solutions developed specifically for aluminum have a large potential impact on energy consumption and cost in this application alone. Outside of heat exchanger applications, an antifouling coating for aluminum would be valuable in the spaces of construction products - such as aluminum roof panels and coverings ?", automotive parts ?" like wheels, engine tubes and cases as well as the bodies of off-road vehicles -, aerospace ?" airplane parts and bodies- and mining equipment. All such surfaces may be exposed to a variety of challenging environments and may be difficult or expensive to clean and would therefore benefit from a fouling-resistant, easy-cleaning treatment.