The future of materials trends toward lighter and stronger. Achieving both of those properties is a difficult task as the two are often inversely proportional. The future of technology may come from nanoscale engineering where convention is often upended. By selectively designing materials, stronger, lighter, more reliable structures are made possible.
Although the benefits of nanotechnology have been theorized about for decades, bringing about practical applications has been somewhat elusive. A novel method of material engineering through additive manufacturing has shown some impressive results. The technique allows for material and structural engineering to be combined at the micro and nanoscales.
That brings us to Nanoscribe and researchers at the Karlsruhe Institute of Technology.
The idea is to achieve the high specific strength of foams and cellular materials through a combination of material properties and open structure. This same principle is used in honeycomb, sandwich structures as well as in many architectural designs.
The researchers used a Nanoscribe 3D-DLW in the Dip-in Laser Lithography configuration to create microscale structures with engineered, hierarchical design. The equipment uses photoresist (common in silicon processing) as a high-resolution polymer base material. The structures were then coated with varying nanoscale thicknesses of alumina (Al2O3) using atomic layer deposition.
As described in an article in Proceedings of the National Academy of Science of the United State of America, “The alumina coating carries tensile and compressive forces, whereas the light polymeric core serves to prevent early face buckling and to improve toughness.”
This customizable material/structural design allows for optimizing strength. Whereas natural and synthetic foams often possess randomness in their structure which restricts performance, the 3D printed structures are entirely controlled. “Depending on the stiffness of junctions, collapse mechanisms are less urgent and topologies may be designed so that a maximum of structural elements are arranged in loading direction, without risking early global buckling.”
The future of engineering may be headed toward smarter materials and structures. Engineering efforts such as this are a welcome confirmation that there is still a lot to anticipate from both 3D printing and nanotechnology.
The published article on the work is available as open access and is definitely worth a look, even if only to see some of the creative structures and testing. The video below shows the loading and failure of one these microscale structures.
Image courtesy of Nanoscribe