Preparation and gas permeation of immobilized fullerene membranes

Fullerene-dispersed membranes were homogeneously prepared under the conditions in which a 10 wt% polystyrene solution containing 1 wt% fullerene was dried under a reduced pressure of 50 cmHg at room temperature. The fullerene membranes prepared with 1,2-dichlorobenzene were found to have the darkest color, and showed no evidence of fullerene crystals in their photomicrographs. UV-visible and infrared absorption spectra of the fullerene membranes showed fullerene bands, which indicated that the fullerene was homogeneously dispersed in the membranes. The permeability coefficients of pure nitrogen, oxygen, carbon dioxide, ethane, and ethylene were found to increase significantly in the fullerene membranes compared to those in the polystyrene membranes, although the ideal separation factors for oxygen/nitrogen and ethylene/ethane in the fullerene membranes (i.e., 4.3 and 1.7, respectively) were slightly less than the separation factors in the polystyrene membranes. The permeability increase originated from the increase in diffusion coefficients in the fullerene membranes.