Can we beat mother nature at materials design?

This comprehensive assessment provides new inspiration and understanding of design principles that may lead to more efficient synthetic approaches for advanced, lightweight structural materials for transportation, buildings, batteries, and energy conversion.

In the natural world, many of the structural materials (wood, shells, bones, etc.) are hybrid materials made up of simple constituents that are assembled at ambient temperatures and often have remarkable properties. Even though the constituent materials generally have poor intrinsic properties, the superior extrinsic properties of the hybrid materials are the result of the arrangement of hard and soft phases in complex hierarchical architectures, with dimensions spanning from the nanoscale to the macroscale. The resulting materials are lightweight and usually show interesting combinations of strength and toughness, even though these two key structural properties tend to be mutually exclusive. It is relatively easy to make materials that are strong or tough, but difficult to make materials that are both.

The scientists review common design motifs of a range of natural structural materials and lessons learned by understanding how the components of the structure work together to produce materials with superior properties. The authors identified two fundamental challenges in the field of bioinspired materials: (1) approaches to take advantage of nature's design motifs in a wider range of material combinations and (2) practical methods to make strong, tough bulk materials.

Future nature-inspired techniques include advanced additive manufacturing (for example, 3D printing) and casting.

This work was supported by the DOE, Office of Science, Office of Basic Energy Sciences (LBNL); National Science Foundation (Dartmouth University); and the European Commission (Imperial College).