Stage-1 cationic C60 intercalated graphene oxide films

Abstract A “stage-1” intercalated film has been made by the ion exchange of pyrrolidinium-functionalized C60 (C60(Py)n+) into centimeter-wide, micrometer-thick air-dried graphene oxide (G-O) films composed of tens of thousands of layers of stacked/overlapping G-O platelets, denoted [C60(Py)n+]G-O films. Spontaneous intercalation by ion exchange of one layer of C60(Py)n+ between adjacent G-O layers expands the interlayer spacing of the films from 0.74 nm to 1.46 nm. The films remain intact in water and various organic solvents, which is likely due to a strong affinity between C60(Py)n+ and G-O. Membranes made of the films showed a 6.8 times faster water vapor permeation rate (allowing the vapor to transport through the membrane almost freely) and a 10.5 times faster liquid water permeation rate than G-O membranes. Heating the films at 2000 °C under applied pressure or at 2700 °C without physical confinement converted them into highly graphitized structures.