Size Effects in Carbon Nanotubes

The intershell spacing of multi-walled carbon nanotubes was determined by analyzing the high resolution transmission electron microscopy images of these nanotubes. For the nanotubes that were studied, the intershell spacing ˆ d002 is found to range from 0.34 to 0.39 nm, increasing with decreasing tube diameter. A model based on the results from real space image analysis is used to explain the variation in intershell spacings obtained from reciprocal space periodicity analysis. The increase in intershell spacing with decreased nanotube diameter is attributed to the high curvature, resulting in an increased repulsive force, associated with the decreased diameter of the nanotube shells. [S0031-9007(98)06983-X]