Reinforcement of single-walled carbon nanotube bundles by intertube bridging.
During their production, single-walled carbon nanotubes form bundles. Owing to the weak van der Waals interaction that holds them together in the bundle, the tubes can easily slide on each other, resulting in a shear modulus comparable to that of graphite. This low shear modulus is also a major obstacle in the fabrication of macroscopic fibres composed of carbon nanotubes. Here, we have introduced stable links between neighbouring carbon nanotubes within bundles, using moderate electron-beam irradiation inside a transmission electron microscope. Concurrent measurements of the mechanical properties using an atomic force microscope show a 30-fold increase of the bending modulus, due to the formation of stable crosslinks that effectively eliminate sliding between the nanotubes. Crosslinks were modelled using first-principles calculations, showing that interstitial carbon atoms formed during irradiation in addition to carboxyl groups, can independently lead to bridge formation between neighbouring nanotubes.
Kis
A
A
Institute of Physics of Complex Matter, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland.
Csányi
G
G
Salvetat
J-P
JP
Lee
Thien-Nga
TN
Couteau
E
E
Kulik
A J
AJ
Benoit
W
W
Brugger
J
J
Forró
L
L
D001610:Beta Particles; D003432:Cross-Linking Reagents; D008854:Microscopy, Electron; D037742:Nanotubes, Carbon / Q000737:chemistry* / Q000528:radiation effects / Q000648:ultrastructure; D013718:Tensile Strength
D003432:Cross-Linking Reagents; D037742:Nanotubes, Carbon