Normally, metal processing requires very high temperatures and high pressure. However, scientists in Singapore have now demonstrated a method that can produce very pure metal structures at room temperature. The exoskeletons of crabs and insects served as a model.
From the days of blacksmiths using furnaces and anvils to the massive, energy-guzzling industrial plants of today, bending metals 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 made primarily of a tough protein called chitin, which hardens through tanning and dehydration. Chitin and other related molecules such as chitosan can then absorb metal particles from the environment, strengthening the animals’ shells.
Scientists at the Singapore University of Technology and Design (SUTD) have now used this ability to create metal structures at room temperature and pressure. The researchers prepared colloidal metal mixtures and then poured them into small amounts of chitosan dissolved in water.
As the water evaporates from the mixture, the chitosan molecules begin to pull the metal particles together in a similar way to how these armored animals work.
The end result is a continuous, solid piece of metal in the desired shape with a purity of 99.5%. Not only do these structures have the properties of metals, including good electrical conductivity, but – even more interestingly – they are compatible with other biomaterials, even with just a small amount of chitosan added. This means they could be incorporated into materials such as wood and cellulose.
Although the metals produced using this method are not particularly strong, the team says this could still be a useful method for producing some metallic components for electronic devices. 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
