A new and easy method for making well-organized micrometer-sized carbon tubes and their regularly assembled structures

Partially ordered micrometer-sized carbon tubes several centimeters in length have been prepared via a new chemical approach by the pyrolysis of composite fibers consisting of a thermally more stable polypyrrole (PPy) skin layer and a poly(ethylene terephthalate) core. The wall thickness of resultant hollow carbon tubes was found to be directly proportional to the thickness of the original PPy coating. Elemental analysis results indicated that these tubes essentially consisted of pure carbon, accompanied by a small amount of N (<3 wt %) and H (<1 wt %). The use of single-pulse magic-angle-spinning solid-state C-13 NMR showed that the carbon of these tubes was unsaturated in nature. The XRD diffraction pattern for the ground-up carbon tubes formed at 1000 degrees C showed two diffraction bands with the maxima at 2 theta = 25.86 degrees and 43.8 degrees, which is equivalent to a d spacing of 3.45 and 2.07 Angstrom, respectively. The Raman spectrum for the same tubes showed two bands at ca. 1354 and 1584 cm(-1). This new method enables the control of both the diameter and wall thickness of the carbon tubes. Most interestingly, it also provides a feasible method for the preparation of two- or three-dimensional well-organized carbon tube assembly from suitable woven fabrics or structures.