Description: The space suit contains metallic bearings at the wrist, neck, and waist, which are exposed to the space environment. There is a need to maintain a high degree of insulation on the surface of the metallic bearings. Current methods to preserve the insulation feature include the use of anodized coatings and polyimide films. However, they are easily damaged and are hard to replace or repair. Innovations are needed to provide a protection method that is easy to maintain. Working with a developer and supplier of systems to NASA, we propose to demonstrate the feasibility of a self-healing insulative polymer coating on the metallic parts that will allow the coating to repair damages under normal operational conditions of the spacesuit. The self-healing capability is afforded through a novel polymer morphology. In Phase I, we will coat 17-4 PH stainless steel flat panels, test coating properties, and evaluate the self-healing performance under near ambient temperatures. In Phase II, the self-healing coating will be applied on a prototype metallic bearing and the coating composition and morphology will be optimized so that it meets all the functional performance requirements. A functioning prototype metallic bearing will be delivered to NASA. The goal is to achieve TRL 6 by the end of the Phase II program.

Benefits: In addition to the specific application identified above, the self-healing coating can find applications in different components of expandable structures for lunar and Martian missions in the future. Expandable structures could benefit from use of the coatings as it would enhance the functionality and reliability of the inflatable structures. The self-healing coatings can be applied to fabrics and films that will be used for lunar habitats. The use of self-healing can help reduce the loss of consumables in the lunar habitat and advance the design of smart structures. Nanostructured coatings could be extended to use to different components of Space Suit Assembly like imparting self-repairing the gloves used for Extra Vehicular Activity (EVA) since the gloves are exposed to possibility of damage.

Potential commercial applications for a self-healing electrically-insulating adhesive are various. The adhesive can be applied to automotive or industrial electronics which may be difficult to access, but would require lower maintenance costs due to the self-healing capability. Similarly, electrical/optical cables and communication devices that are in hard-to-reach or hazardous locations can use this adhesive as a means to improve the safety of technical repair personnel. By extension, these adhesives can be used in protective equipment for technical personnel who work in environments where electrical shock is a concern. Another huge area of potential interest is chromate free self-healing corrosion resistant coatings for metals, an example of which is aluminum alloys used for aircraft components and fuel tanks. Current non-chromate coatings cannot match the performance of chromate coatings. Introduction of a barrier coating with near ambient temperature self-healing function will provide another tool toward establishing a chromate-free system with performance equivalent to that of a chromate-containing coating.