Polygonization of single-wall carbon nanotube bundles under high pressure - art. no. 153401

The pressure-induced structural changes of single-wall carbon nanotubes org anized into two-dimensional crystalline bundles are studied by neutron diff raction up to similar to 50 kbar. The strong variation of the (10) Bragg pe ak position with pressure is interpreted as a progressive deformation of th e tube section from circular to hexagonal, in addition to the van der Waals compression. Data at 50 kbar suggest that the tubes are closed to be fully polygonized at this pressure. The anisotropic behavior of the patterns wit h pressure is assigned to the presence of a uniaxial pressure component and to preferential orientations of the bundles.