Groovy key to nanotubes in 2D

Ultrathin carbon nanotube crystals could have wondrous uses, like converting waste heat into electricity with near-perfect efficiency, and Rice University engineers have taken a big step toward that goal. They turned a mob of unruly nanotubes into a well-ordered collective. Of their own accord, and by the billions, nanotubes were willingly lying down side by side, like dry spaghetti in a box. But the reason for that behavior has not been revealed – until now: Tiny parallel grooves in the filter paper — an artifact of the paper’s production process — cause the nanotube alignment.