The image below plots the projected charge-density in a multi-walled version of the internal termination above, made with real atoms. This image in turn is only tiny part of a much larger high-resolution transmission electron microscope (electron phase contrast) image field. The curved parallel lines in this closeup represent edge-on graphene sheets, wrapped with graphite's typical 3.4 to 4+ Angstrom inter-layer spacing and with azimuthal symmetry around the axis of the tube. The bright "triangles" (circled) at opposite ends of the internal termination highlight ends in projection of the "inner-tube like" toroidal void formed between the terminated layers and the 9 outer layers which run parallel to the tube axis un-deterred. Questions: Which of the tube walls (e.g. 1, 9, or 15) was likely put into place first during construction of this object? Also, is it likely that the internal termination was grown in from the beginning, or only added after the fact? Finally, from the observed "in-sheet" spacing, can you tell whether this tube's layerings are arm-chair, zig-zag, or some mixture?
Below find a low-res version of that larger image of multi-walled carbon nanotubes, lying like straight sticks of uncooked spaghetti after falling out of the box into a pot on the stove. To put their size into perspective, note that the black ID bar at the bottom of the 240,000x negative is 14[mm] wide. It therefore represents a distance on the specimen of about 14[mm]/240000~58[nm]. Hence the width of the image is only about a third of a micron.
The large tilted and textured Y-fork on the right hand side of the image is part of the lacey-carbon support film, while the dark clumps in the center and center-left are likely excess carbon and/or catalyst particles involved in nanotube growth. Challenge: Can you locate the above-shown closed-off region of a fifteen-wall nanotube in the picture below? Is it difficult to find, and if so why?
Do not click here unless you: (i) are desperate to see a rotated version of the above image with that defect region highlighted, (ii) admit to complete and abject failure at identifying the defect yourself, and (iii) give up! Curiosity to check your conclusions against ours also qualifies, if you've already done what you're able to do. An intermediate magnification "spoiler" may be found here, which in addition provides clues to the lattice structure of that darker tube in the image.