Structure/property relationships for poly(vinylidene fluoride)/doped polyaniline blends

Poly(vinylidene fluoride) (PVDF) and its blends with polyaniline (PANI) doped with dodecylbenzene sulfonic acid (DBSA) were characterized by electrical conductivity, differential scanning calorimetry (DSC) and X-ray scattering techniques. The onset of an infinite cluster (InC) of conducting, highly anisometric PANI/DBSA particles in PVDF/(PANI/DBSA) blends was observed at the percolation threshold as low as w* approximate to 3.5 wt.%. The small angle X-ray scattering (SAXS) data confirmed the expected spatial organization of PANI/DBSA needles into fractal-like structures above w*. A slight decrease of both the DSC and the wide-angle X-ray scattering (WAXS) degrees of crystallinity of PVDF with the PANI/DBSA mass content w was explained by strong interactions at the PVDF/(PANI/DBSA) interface resulting in the loss of crystallizability of a fraction of sterically immobilized chains of PVDF in boundary layers around PANI/DBSA particles. The available data suggest that the conductive paths within InC of PANI/DBSA in PVDF/(PANI/DBSA) blends were formed primarily by the end-to-end contacts of PANI/DBSA fibrils.