Buckyballs Self-Assembly Mystery Solved

By Michael Horton •  Updated: 07/31/12 •  3 min read

buckyballsAfter 25 years of research, scientists have solved the question of how the family of caged-carbon molecules known as buckyballs form. The results shed essential light on the self-assembly of carbon networks and should have significant implications for carbon nanotechnology. Findings may also offer insight into the origin of space fullerenes, found throughout the universe.

The buckyball, also known to scientists as buckminsterfullerene, carbon 60, or C60, is familiar to many students from the covers of their school chemistry textbooks, in fact, the molecule represents an iconic image of “chemistry.”

However, the exact way these often exceedingly symmetrical, gorgeous molecules with mesmerizing properties are formed in the first place has been a mystery for a quarter-century. Despite worldwide investigation since the discovery of C60 in 1985, buckminsterfullerene and other, non-spherical C60 molecules, known collectively as fullerenes, have kept their secrets. This is because they are born under highly energetic conditions and grow ultra-fast, making them difficult to analyze.

“The difficulty with fullerene formation is that the process is literally over in a flash — it’s next to impossible to see how the magic trick of their growth was performed,”

said Paul Dunk, a doctoral student at Florida State and lead author of the work.

Heavy Metal and Fullerene Molecules

The scientists detail their original approach to testing how fullerenes grow in a study, published in the journal Nature Communications.

“We started with a paste of pre-existing fullerene molecules mixed with carbon and helium, shot it with a laser, and instead of destroying the fullerenes we were surprised to find they’d actually grown,”

they wr1te. Fullerene molecules were able to absorb and incorporate carbon from the surrounding gas.

By using fullerenes containing heavy metal atoms in their centers, the scientists were able to show that the carbon cages remained closed throughout the process.

The researchers worked with a team of chemists using the MagLab’s state-of-the-art 9.4-Tesla Fourier transform ion cyclotron resonance mass spectrometer to analyze the dozens of molecular species produced when they shot the fullerene paste with the laser. This instrument works by separating molecules according to their masses, allowing the researchers to identify the types and numbers of atoms in each molecule. The process is used for applications as diverse as identifying oil spills, biomarkers, and protein structures.

The buckyball research results will be important for understanding fullerene formation in non-terrestrial environments. Recent reports by NASA showed that crystals of C60 are in orbit around distant suns. This suggests that fullerenes may be more common in the universe than previously thought.

“The results of our study will surely be extremely valuable in deciphering fullerene formation in extraterrestrial environments,”

said Florida State’s Harry Kroto. Kroto won a Nobel Prize for the discovery of C60 and is a co-author of the current study.

The results also provide elemental insight into the self-assembly of other technologically important carbon nanomaterials such as nanotubes and the new wonder element of the carbon family, graphene.

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