Scientists have discovered the oldest known human-made nanomaterials in ancient artifacts in Tamil Nadu
New Delhi:
Scientists have discovered the oldest known human-made nanomaterials in the “unique black coatings” of ancient pottery shards, dating back to 600 BC. C., unearthed from an archaeological site in Keeladi, Tamil Nadu.
The research, published recently in the journal Scientific Reports, revealed that these coatings are made of carbon nanotubes (CNTs) that have allowed the layer to last for more than 2,600 years, raising questions about the tools used during those periods to achieve high manufacturing temperatures. earthenware.
According to scientists, including those at the Vellore Institute of Technology (VIT) in Tamil Nadu, the coatings are “the oldest nanostructures observed so far.”
“Until this discovery, as far as we know, the oldest known nanostructures in human-made artifacts are from the 8th or 9th century AD,” study co-author Vijayanand Chandrasekaran of the Vellore Institute of Technology told the Press Trust of India news agency.
Carbon nanotubes are tubular structures of carbon atoms arranged in an orderly fashion, Chandrasekaran said, adding that coatings on old artifacts may not last as long due to wear and tear caused by changing conditions.
“But the robust mechanical properties of the CNT-based coating have helped the layer last for more than 2,600 years,” he added.
Carbon nanotubes have superlative properties, including high thermal and electrical conductivity, and very high mechanical strength, explained nanomaterials scientist MM Shaijumon from IISER Thiruvananthapuram, who was not related to the study.
“But it is possible that people of this time did not add CNTs intentionally; instead, during high temperature processing, these would have been formed accidentally,” Shaijumon told the PTI news agency.
“If there is any processing of the potteries, which probably would have involved some high-temperature treatment, then it will add more justification to the findings,” he added.
According to Mr. Chandrasekaran, the closest scientific explanation for the finding is that some “fluid or plant extract” could have been used in the linings of these containers, which could have led to the formation of CNT during high temperature processing. .
Rajavelu S, a history professor at Alagappa University in Tamil Nadu, who was not related to the study, told the PTI news agency that people around this time may have added or covered something similar to the sap of the plant in the inside the pots, and subjected to the nearly 1100-1400 degrees Celsius of high temperature fire treatment as seen in ovens.
“This fire treatment may have led to the formation of the liner that has likely strengthened the pot and made the liner durable,” Rajavelu said.
“Normally with high-temperature processing of carbon, they form these kinds of tubular nanostructures, but until about the 1990s there were no sophisticated instruments available to characterize them. So these structures are already present in nature and we are only now looking at them.” explained Mr. Shaijumon.
Lord Rajavelu agreed.
He said ancient people would not have known them as CNT, but they may simply have had a need to make their pots have high durability, “and they may have needed a certain color in their products when applying high temperature cooking. “.
“They probably knew the technique for making these coatings in practice, but they may not have known this as a thesis with any kind of formulas,” Rajavelu added.
Commenting on the importance of the research, Sharada Srinivasan, an archeometallurgy expert associated with the National Institute for Advanced Studies (NIAS) in Bengaluru, said that nanotechnology has advanced since the 1990s with the advent of advanced techniques such as tunnel microscopy. sweep.
“But archaeological studies increasingly recognize that skilled craftsmen of the past sometimes accidentally or empirically made nanomaterials, such as the famous Egyptian blue, without being aware of the science of nanoscale work,” Srinivasan told the Press Trust of India. .
Based on his analysis, Chandrasekaran said that the ancient Tamil civilization of this time was aware of and mastered high-temperature processing, but added that the means and mechanisms by which they produced these carbon nanotube artifacts are not widely explored.
“The black and red pottery associated with megalithic sites in South India continues at Keeladi, which dates back to the 6th century BC. The fine black and red effect was achieved by high temperature firing temperatures of about 1100 degrees in the presence of matter rich in carbon and iron – rich red soils, “said Ms Srinivasan.
“They don’t look like normal pots, they have glazed finishes and are made of high-quality clay,” Rajavelu added.
He said that these clay objects were probably used by “sophisticated people of the time,” adding that “many of the fragments” have been found at Keeladi, “some of which date as far back as 900 BC”
“We have known for a long time that in iron smelting and manufacturing, India was a world leader at that time. Even the ancient Tamil literature from Sangam has highlighted steelmaking,” Rajavelu said.
“The technological abilities of the Tamils in the high temperature manipulation of carbonaceous matter to make the ultra-high carbon crucible steel known as wootz towards the mid to late centuries BC were also reported by us, while nanotubes Carbon were reported in medieval stamped ‘Damascus’ blades forged from that steel,’ explained Ms Srinivasan.
She believes the findings expand the broader understanding of the history of science and technology in India, and point to possible future applications of nanomaterials as durable coatings.
(Except for the headline, this story has not been edited by NDTV staff and is posted from a syndicated feed.)
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