Just like Lamarck’s giraffes stretched their necks to reach the food on the highest branch, researchers at Rice University are growing carbon nanotubes using a carbon food source.
While Lamarck’s theory of evolution was disproven by Darwin’s natural selection, nanotubes can be grown and selected based on how they grow toward a food source. The research, led by Boris Yakobson and Ksenia Bets at Rice University, was published in Science Advances on November 9.
Carbon nanotubes are rolled-up sheets of graphene, single-layer carbon structures arranged in a hexagonal lattice. They are challenging to make but incredibly strong, light, tensile, and biocompatible. Carbon nanotubes have a variety of uses, like sports equipment, vehicles, electronics, or even armor.
Normally, nanotubes grow randomly and can be single- or multi-walled. However, carbon nanotubes with specific wall thickness and chirality (how the hexagons are aligned) have different applications, but separating nanotubes by category can be costly and time-consuming.
Bets and Yakobson may have discovered a way to control for chirality using a carbon feedstock to direct the growth of carbon nanotubes. The nanotubes grew on a metal catalyst and followed the direction of the hot carbon gas being pumped out of a nozzle.
As long as the catalyst was active, the nanotubes would grow at different speeds. Tubes with different chiralities grow at different rates, so in theory, scientists could eliminate unwanted chiralities based on the length of the nanotubes.
The growth of these tubes isn’t random, and since there are a finite number of chiralities, the tubes would grow in tiers, meaning that it would be possible to select the fastest growing tubes, or the second fastest, and so on. The nanotubes that grow the quickest are likely too reactive, so the researchers recommended selecting slower-growing nanotubes.
The research is still in its early stages since the paper was the proposal of a technique and didn’t include experimental data. Bets hopes that more laboratories are inspired to test out their theory.
“In terms of science, it’s usually more beneficial to give ideas to the crowd,” she said in a release from Rice University. “That way, those who have interest can do it in 100 different variations and see which one works. One guy trying it might take 100 years.”