Researchers in North Carolina and Houston have developed a new self-healing composite material that is stronger than those currently used in aircraft wings and wind turbine blades and can repair itself more than 1,000 times. It is estimated that this self-healing ability could extend the lifespan of conventional fibre-reinforced composite materials from a few decades to several centuries.

Fibre-reinforced polymer composites are made from layers of fibres, such as glass or carbon, bonded together with a polymer material, often epoxy. The new self-healing approach focuses on interlaminar delamination, a common type of damage where cracks form and cause the fibre layers to separate from the surrounding matrix.

The new material closely resembles standard fibre-reinforced composites but includes two key additions. First, the researchers use 3D printing to apply a thermoplastic healing material onto the fibre layers, creating a patterned interlayer that improves resistance to delamination by two to four times. Second, thin carbon-based heating layers are embedded within the composite. When an electrical current is applied, these layers heat up, melting the healing material so it can flow into cracks and re-bond the damaged areas.

Patrick noted that the technology would be especially valuable for large and costly systems such as aircraft and wind turbines. He added that it could be even more important for spacecraft, which operate in environments where on-site repairs are extremely difficult or impossible.