Abstract

We carry out two experiments: (1) the formation of clusters composed of C₆₀ molecules via self-assembly and (2) the reinforcement of the clusters. Firstly, clusters such as fibres and helices composed of C₆₀ molecules are produced via self-assembly in supercritical carbon dioxide. However, C₆₀ molecules are so weakly bonded to each other in the clusters that the clusters are broken by the irradiation of electron beams during scanning electron microscope observation. Secondly, UV photons are irradiated inside a chamber in which air is filled at 1 atm and the above clusters are placed, and it was found that the clusters are reinforced; that is, they are not broken by electron beams any more. C₆₀ molecules located at the surface of the clusters are oxidised, i.e. C₆₀O_n molecules, where n = 1, 2, 3 and 4, are produced according to time-of-flight mass spectroscopy. It is supposed that oxidised C₆₀ molecules at the surface of the clusters may have an important role for the reinforcement, but the actual mechanism of the reinforcement of the clusters has not yet been clearly understood and therefore is an open question.