Metalworking usually requires very high heat and pressure, but scientists in Singapore have now demonstrated a way to make very pure metal structures at room temperature. Inspired by the exoskeletons of crabs and insects.
From the days when blacksmiths used furnaces and anvils to today’s massive energy-consuming industrial facilities, bending metal to our will requires a lot of heat, energy, and effort. But as with many things, nature may have found a way long ago.
Metallic compounds are sometimes found in the hard exoskeletons of arthropods such as crabs, lobsters, insects, and spiders. These shells are mostly composed of a tough protein called chitin, which hardens through tanning and dehydration. Chitin and other related molecules such as chitosan can then attract metal particles from the environment to strengthen the animals' shells.
Now, scientists at the Singapore University of Technology and Design (SUTD) have used this ability to produce metal structures at room temperature and pressure. The researchers made colloidal mixtures of metals, then poured them into a small amount of chitosan dissolved in water.
As the water in the mixture evaporates, the chitosan molecules begin to attract the metal particles together, like armored animals.
The result is a continuous piece of solid metal with 99.5% purity, in the desired shape. Not only do these structures have the properties of metals, such as good electrical conductivity, but more interestingly, they are compatible with other biomaterials, even with only a small amount of chitosan added. This means they can be incorporated into materials such as wood and cellulose.
While the metals produced by this method are not particularly strong, the team says it could still be a useful way to produce some metallic components for electronics. The next step is to further develop the process to produce biodegradable electronic components.
The research was published in the journal Advanced Functional MaterialsThe team demonstrates the technique in the video below.
Production of electrically conductive biological objects under ambient conditions
Source: SUTD via Asia Research News