Morphology of (KC60)n Polymeric Fibers

The bers produced by co-evaporation of C 60 and potassium, and subsequent treatment in toluene, have been investigated by electron microscopy and optical spectroscopy. The electron diiraction pattern can be indexed in terms of the known orthorhombic (KC 60) n structure. The frequencies of the vibrational modes indicate charge transfer between the K and the C 60 , similar to bulk samples; no anisotropy of optical properties has been observed. The detailed analysis of the electron diiraction and micrographs reveal that, contrary to expectations, the direction of polymerization does not coincide with the direction of the long axis of the bers. Furthermore, the structure is twinned, explaining the absence of optical anisotropy.