Nanostructured Polyaniline Emeraldine-base form (EB-PANI): a structural investigation for different neutralization times

Polyaniline Emeraldine-base form (EB-PANI) was chemically obtained through the neutralization of Polyaniline Emeraldine-salt form (ES-PANI) using NaOH 0.5 M at 3, 24 and 48 h of neutralization. X-ray Diffraction (XRD), Le Bail Method, Small-angle X-ray Diffraction (SAXD), Small-angle X-ray Scattering (SAXS) and Scanning Electron Microscopy (SEM) were used to characterize the obtained polymers. EB-PANI crystal data obtained at 3 h of neutralization were a = 5.7230 Å, b = 17.7233 Å, c = 19.2336 Å, α = 85.2879°, β = 84.6952° and γ = 87.7014°. Crystallinity percentage was obtained using the XRD patterns and remained around 32% during the neutralization process. Le Bail Method revealed that the crystallites were very small lamellae with an oblate spherical shape and global average size around 33 Å. By SAXS it was obtained the particle Radius of Giration (Rg) around 200 Å. The maximum particle size (Dmax) of 550 Å was obtained from the Pair-distance Distribution Function (p(r)). SEM images showed very small nanofibers morphology formed by interconnected nonhomogeneous nanospheres. EB-PANI electrical conductivity was 1.32 × 10−7 S/cm along the neutralization process.