N14A-T013 TITLE: Durable Low Adhesion Anti-Icing and Ice-Phobic Surfaces

TECHNOLOGY AREAS: Ground/Sea Vehicles, Materials/Processes

ACQUISITION PROGRAM: PEO-Ships (R. Mitchell), PMS 400F (E. Macfarlane), NAVSEA 05T (M. Bosworth)

OBJECTIVE: Develop and demonstrate robust and affordable anti-icing surfaces (prevent ice formation) that are also ice-phobic (reduce ice adhesion to substrates) for superstructure ice protection of surface ships in Arctic operations with no unacceptable ship and environmental impacts.

DESCRIPTION: Ship superstructure icing decreases seaworthiness, reduces deck safety, and risks mission success by reducing electronics and machinery performance. Ice is currently removed manually with baseball bats, chemicals and shovels, a hazardous operation in Arctic cold in high seas with risk of damaging ship components. Novel passive ice protection technologies are needed that do not require personnel on deck and maintain high performance of ship components during and after icing conditions. Many anti-icing materials have been demonstrated in the laboratory, and some have had limited field tests, but there has been little rigorous testing in operational environments. Anti-icing, typically superhydrophobic, surfaces delay drop freezing allowing them to roll off of surfaces before freezing. However, they can be defeated by frost, snow, and high winds driving drops into the surface, making an additional ice-phobic capability also desirable.

In this program, novel passive, not requiring power, anti-icing materials that are also ice-phobic will be developed that will meet the following performance requirements:

(1) Ice adhesion strength less than 30 kPa that will be proven by an independent government laboratory through repeated tests.
(2) Operate effectively in temperatures down to -30�C in salt water and fresh water.
(3) Durable and abrasion resistant in simulated or actual operating environments, warm and cold. Vendor must demonstrate anti-icing and deicing capability and durability of the surface for the equivalent of one year of ship-board use (multi-season) in Beaufort Sea or Chukchi Sea conditions.
(4) Affordable manufacturing techniques for covering ship superstructures and hulls (cost effectiveness).
(5) Ease of application to ship superstructures and other deck equipment (cost effectiveness), including recoat over existing material, or material removal if necessary.

In addition, resistance to corrosion, mild acids, UV, organisms and organic phosphates; optical transparency (>80% in the visible regime); slipperiness on decks; compatibility with current low solar absorbing ship paints; RF transparency; and radiation and recoat frequency should be considered. The infrared and millimeter wave (MMW) signatures of coatings are also critical to ship survivability.

PHASE I: Develop and demonstrate theory and proof of concept for proposed material. Demonstrate capability of the proposed low adhesion anti-icing/ice-phobic surface and manufacturing processes for making the materials to meet the requirements specified above. Laboratory scale flat coupons with minimal size of 30cm x 30cm should be fabricated by the vendor and characterized for its performance in a relevant environment at a government-designated testing facility (the US Army�s Cold Regions Research and Engineering Laboratory (CRREL) in New Hampshire is one of the candidates).

PHASE II: Based on Phase I development and demonstration, improve manufacturing processes considering affordability and ease of applications for large area coverage. Conduct systematic performance evaluation of larger scale prototype low adhesion anti-icing/ice-phobic surface with minimal size of 1m x 1m to assess the capability of meeting the requirements specified above in the government-designated laboratory. Repeated and accelerated testing will be performed to assess durability of the specimens.

PHASE III: Produce large area anti-icing/ice-phobic surfaces and apply to a platform (either a ship or a stationary off-shore structure to be determined by the government) and test in the real arctic operational environment.

PRIVATE SECTOR COMMERCIAL POTENTIAL/DUAL-USE APPLICATIONS: Successful development of the low adhesion anti-icing/ice-phobic surfaces that are durable and easy to apply to a large area will benefit an enormous range of commercial applications including marine transportation in the Arctic regions, commercial airplanes before flight (deicing), and the power industry (prevent ice accumulation on power lines).

REFERENCES:
1. Bahadur, B., Mishchenko, L., Hatton, B., J. Ashley Taylor, J.A., Aizenberg, J. and Krupenkin, T. (2011), Predictive Model for Ice Formation on Superhydrophobic Surfaces, Langmuir, 27, pp14143�14150.

2. Cao, L., Jones, A.K., Sikka, V.K., Wu, J., Gao, D. (2009), Langmuir, 25, pp12444-1244.

3. Kulinich, S. A., Farhadi, S., Nose, K., Du, X.W. (2011), Langmuir, 27, pp25-29.

4. Makkonen, L. (2012), Ice Adhesion � Theory, Measurements and Countermeasures, J. Adhesion Science & Technology, 26, pp414-445.

5. Meuler, A.S., Smith, J.D., Varanasi, K., Mabry, J., McKinley, G.H. and Cohen, R.E. (2010), ACS Applied Materials & Interfaces, 2(11), pp3100-3110.

6. Ryerson, C.C. (2009), Assessment of Superstructure Ice Protection as Applied to Offshore Oil Operations Safety, ERDC/CRREL TR-09-4 (http://www.crrel.usace.army.mil/library/technicalreports/ERDC-CRREL-TR-09-4.pdf).

7. Ryerson, C.C. (2011), Ice protection of offshore platforms, J. Cold Regions Science and Technology 65, pp 97-110.

8. Ryerson, C.C. (2013), Icing Management for Coast Guard Assets, ERDC/CRREL TR-13-7 (http://acwc.sdp.sirsi.net/client/search/asset/1027480).