Scientists have discovered the oldest human-made nanostuctures in the “unique black coatings” of ancient pottery shards dated to 600 BC, found from an archeological site in Keeladi, Tamil Nadu.
The research, revealed that these coatings are made of carbon nanotubes which have enabled the layer to last more than 2600 years, raising questions on the tools used during those periods to achieve high temperatures for making earthen wares.
“Until this discovery, to our knowledge, the most ancient known nanostructures in human-made artifacts are from the eighth or ninth century AD,” study co-author Vijayanand Chandrasekaran from Vellore Institute of Technology told.
“But the robust mechanical properties of the CNT based coating has helped the layer sustain more than 2600 years,” he added. “But the people of this time may not have intentionally added CNTs, instead, during the processing at high temperatures, these would have just formed accidentally”. “If there is some processing of the potteries, which probably would have involved some high-temperature treatment, then it will add more justification to the findings,” he added.