"Our interest in advancing new applications for low-dimensional carbon – fullerenes, nanotubes and graphene – is broad," physicist Boris Yakobson commented. "One way is to use them as building blocks to fill 3D spaces with different designs, creating anisotropic, nonuniform scaffolds with properties that none of the current bulk materials have."
When a nanotube grows from graphene, atoms facilitate the turn by forming heptagonal rings, but these hinder the escape of heat.
The Rice researchers discovered through computer simulations that removing atoms from the 2D graphene base would force a cone to form between the graphene and the nanotube, leaving a clear path for heat release.
"The tunability of such structures is virtually limitless, stemming from the vast combinatorial possibilities of arranging the elementary modules," said scientist Alex Kutana. "The actual challenge is to find the most useful structures and then make them in the lab reliably.
"In the present case, the fine-tuning parameters could be cone shapes and radii, nanotube spacing, lengths and diameters. Interestingly, the nano-chimneys also act like thermal diodes, with heat flowing faster in one direction than the other," he concluded.
