Chemical dating carbon
To make his early filaments, Edison formed cotton threads or bamboo slivers into the proper size and shape and then baked them at high temperatures.
Cotton and bamboo consist mostly of cellulose, a natural linear polymer made of repeating units of glucose.
Bacon’s graphite whiskers were sheets of graphite rolled into scrolls, with the graphite sheets continuous over the entire length of the filament.
“After studying the heck out of these things, I finally published a paper in the Journal of Applied Physics in 1960,” Bacon says.
“I would examine these deposits, and when I broke one open to look at the structure, I found all these whiskers,” he says. They were up to an inch long, and they had amazing properties.