Deposition of C60, C70 and C84 fullerene molecules, in benzene via a change of the fluid state, from a gas–liquid two phase region to the critical point

We dissolve C60, C70 or C84 molecules in benzene and change the fluid state from a gas–liquid two-phase region (25.0 °C) to the critical point (289.0 °C) and from the critical point to the original state (25.0 °C) along the gas–liquid coexistence curve. We find that particle-like and whisker-like nano/micro clusters, which are composed of C60 molecules, deposit on the surface of a silicon substrate placed vertically in C60/benzene solution during the temperature change, whereas no appreciable clusters are detected on the silicon substrate in either C70/benzene or C84/benzene solutions. The clusters, in which fcc lattice structures are formed by C60 molecules, remain stable in the solution. The present result suggests that C60 molecules can be separated and extracted from a mixture of C60, C70 and C84 molecules dissolved in benzene.

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► Nano clusters composed of C60 molecules deposit in C60/benzene solution under near-critical conditions of benzene.
► The state of the fluid was changed; a subcritical two-phase region – the critical point – the original two-phase region.
► Fcc lattice structures were formed by C60 molecules in the clusters.
► C60 molecules may be separated and extracted from a mixture of different types of fullerene molecules dissolved in organic solvents.