Researchers from the UK and Sweden have investigated how graphene nanoribbons grow from an anthracene polymer on a gold substrate, using simluations on a supercomputer. They discovered that in the most likely nanoribbon growth process, the gold substrate acts as more than just a support where the reaction can take place. The gold actually catalyzes the reaction.
It turns out that the graphene nanoribbons grow in a way that resembles the domino effect.
More info: http://www.physorg.com/news/2011-09-graphene-nanoribbons-due-domino-like-effect.html