Kis, A.Csanyi, G.Salvetat, J. P.Lee, T. N.Couteau, E.Kulik, A. J.Benoit, W.Brugger, J.Forro, L.2007-04-232007-04-232007-04-23200410.1038/nmat1076https://infoscience.epfl.ch/handle/20.500.14299/5233WOS:000189345100016During 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.electron-beam irradiationion-irradiationelastic-modulusfibersropesdefectsc-60text::journal::journal article::research article