Keezhadi-Cradle of Tamil Civilization-Ep-6
Carbon nanotube coatings have been detected in pottery from Keezhadi, and they have been coated by the settlers. They have managed to withstand more than 2600 years, and they are one of the oldest human-made nanomaterials. In general, most coatings do not survive, but the robust mechanical coating of the same has managed to survive this long. Ancient people need not know that these are CNT, this was a term coined by us recently. Not 2000 years, but just 20 years later, our future generation would wonder why did we build materials in a cheap fashion. These were not ordinary clay pots, but glazed and made with high-quality clay.
There are unique black coatings on the inside of pottery fragments. It has been confirmed by spectroscopy studies. The average diameter of a single-walled carbon nanotube found to be about 0.6 ± 0.05 nm. Nanoparticles give long-standing durability, adhesion, and strength. Ancient day humans knew the tools, methods to synthesize, and they were in the Keezhadi region adds more flavor to this study. Copper and Silver nanoparticles were found in glazed Islamic pottery and the Renaissance region, but from Keezhadi, it is a first, maybe the first of many things to come. Scientists observed the presence of 1-D nanomaterials such as multi-walled carbon nanotubes (MWCNT) in Damascus steel. It explains the superior strength of Damascus steel was due to the presence of carbon nanotubes (CNT).
The reason to read history, is that it repeats itself.
The inner black coating of the shard was studied, and this seems the oldest usage of CNT to date. We Indians, are used to seeing normal fossils, and very old panchaloha idols in our temples. Our greatest temple was built 1000 years back, imagine, that 1000 years back, not until 350 years, the USA did not exist. Our unique temple structures pre-date many histories of the countries. The uniqueness is how did the black coating was retained to be discovered after 2000 years.
The most interesting factor is the smoothness also preserved with less degradation. Among the shards inspected, some pieces still retaining the smooth shiny surface intact. Since the coating is more than 2000 years old unless it possesses robust mechanical and chemical stability to resist or isolate from the varying environmental conditions it becomes practically impossible to be stable for such a long duration. (excerpt from the “Nature” article)
The source of the carbon is not ascertained yet. It is a known fact, that what we call CNT, they might have known by a different name. But the usage in an interior pot, to last long, is proved without doubt. What was made to last long, has really lasted long? We joke ourselves, about how our homes or dams do not last more than a few years, here is workmanship on a simple clay pot, retaining its color, smoothness 2000 years later. Plant-based materials should have been used as a source, heated at high temperature to render tensile strength to it.
Ancient Tamilian did not know this diagram, but knew how to make it, and capture our attention millennia later.
Reference: https://www.nature.com/articles/s41598-020-76720-z
