3D printing technology is being used to build not only things as big as houses but also things as small as snowflakes. New material makes the latter stronger than ever before and prints much faster. The composite, developed by scientists at Stanford University, is used primarily in nanoscale lattice-like structures to protect tiny underlying components (such as those found in electronics). It consists of a polymer resin and tiny clusters of metal atoms, called metal nanoclusters.
In an existing process called two-photon lithography, a laser is shone into a liquid resin mixture. As soon as the very center of that beam hits one of the nanoclusters, a chemical reaction occurs, causing the resin to harden in that particular region. Thus, by moving the laser beam precisely through the resin, it is possible to build up very small and complex objects.
When lattices printed with this special material were tested, they were found to be able to absorb twice as much energy as lattices printed with other commonly used materials. Depending on the type of lattice made from the new composite material, some lattices excel at bearing heavy loads without deforming, while others excel at squashing and deforming to absorb the impact, then bouncing back to their original, undamaged state.
When printing the lattice, the metal nanoclusters allow chemical reactions to occur much faster than in other materials that utilize different types of photosensitive molecules. This effect was not difficult to notice even when a number of different polymers were used in the composites – in one case when a protein-based polymer was used, the items printed 100 times faster than when this polymer was previously used.
Assistant Professor Wendy Gu, corresponding author of a paper on the study, said, “There is now a lot of interest in designing different types of 3D structures to obtain mechanical properties. What we’ve done with this is to develop a material that is really good at resisting forces, so it’s not just a three-dimensional structure, but a material that provides very good protection.”
The paper was recently published in the journal Science.
