The ceramic becomes more electrically conductive under elastic strain and less conductive under plastic strain, and could lead to a new generation of sensors embedded into structures like buildings, bridges and aircraft able to monitor their own health.

The electrical difference caused by the two types of strain was not obvious until Rice University’s Rouzbeh Shahsavari, an assistant professor of civil and environmental engineering and of materials science and nanoengineering, and his colleagues modeled a novel two-dimensional compound, graphene-boron-nitride (GBN).

Under elastic strain, the internal structure of a material does not change. But the same material under plastic strain — caused in this case by stretching it far enough beyond elasticity to deform — distorts its crystalline lattice. GBN, it turns out, shows different electrical properties in each case, making it a worthy candidate as a structural sensor.

Shahsavari had already determined that hexagonal-boron nitride can improve the properties of ceramics. He and his colleagues have now discovered that adding graphene makes them even stronger and more versatile, along with their surprising electrical properties.

The magic lies in the ability of two-dimensional, carbon-based graphene and white graphene to bond with each other in a variety of ways, depending on their relative concentrations. Though graphene and white graphene naturally avoid water, causing them to clump, the combined nanosheets easily disperse in a slurry during the ceramic’s manufacture.

The resulting ceramics, according to the authors’ theoretical models, would become tunable semiconductors with enhanced elasticity, strength and ductility.