Laser printing creates material lighter than water, strong as steel

Ars Technica : Finding materials that are less dense than water and that have high compressive strength is a long-standing goal of material scientists. Now, Jens Bauer of the Karlsruhe Institute of Technology in Germany and his colleagues have succeeded. The group had created some computer models of structures that they believed would meet those criteria, but it was the development of nanoscale 3D printing technology by the company Nanoscribe that made the materials real. Bauer’s group used Nanoscribe’s laser printer to create a variety of structures from a lightweight polymer. They then coated the structures with aluminum oxide to provide additional strength. The strongest of their materials had a nanoscopic honeycomb structure covered with a 50-nm-thick layer of aluminum oxide. The material was less dense than water and able to hold a load of 280 MPa, as strong as some forms of steel. However, the printer Bauer’s team used only creates pieces on a micrometer scale, and Nanoscribe’s largest printer still only produces pieces on a millimeter scale, so the material and technique have yet to find any real-life applications.