Nanostructure evolution during thermal treatment of polyimide–fullerene composites as revealed by WAXS and SAXS

The nanostructure formation in polyimide–fullerene composites during thermal treatment was investigated “in situ”, by means of wide-angle (WAXS) and small-angle X-ray scattering techniques. The WAXS patterns of the PI composites do not reveal the presence of C60 reflections. However, the PI/C60 composite, obtained by adding the C60 solution to the diamines-solution during the first step of the reaction (preparation of the polyamic acid, PAA), shows a maximum at small X-ray scattering angles. Results show that this intensity maximum is markedly affected by thermal treatment of the PI/C60 composite, disappearing at high temperature. From “in situ” X-ray scattering experiments, the “manner” in which the C60 nanoparticles are added to the other reactants and influences the properties of the final polymer is discussed.