Characterization of Poly(o-methoxyaniline) Emeraldine-base form obtained at different time neutralization

• The use of SAXS and XRD provide a systematic study on the structural characterization of polymers.
• LeBail fit represents a recent tool applied in structural researches of polymeric materials.
• EB-POMA has changed slowly its structure under neutralization process.

Poly(o-methoxyaniline) Emeraldine-base form (EB-POMA) was obtained thought the neutralization of the Poly(o-methoxyaniline) Emeraldine-salt form (ES-POMA) using NaOH 0.1 M at 3.0, 24.0 and 48.0 h of neutralization. X-ray Diffraction (XRD), LeBail Fit, Small-angle X-ray Diffraction (SAXD), Small-angle X-ray Scattering (SAXS) and Scanning Electron Microscopy (SEM) were used to characterize the obtained EB-POMA. Crystallinity was obtained from XRD patterns and remained around 38% up 24.0 h of neutralization, decreasing to 27% at 48.0 h. Crystal data (for 3.0 h of neutralization, a = 6.793, b = 9.529, c = 19.640, α = 83.043, β = 84.656 and γ = 88.586) were obtained from LeBail fit and showed crystallites very small lamellae with an oblate spherical shape and global average size around 20 Å. By SAXS it was obtained the particle Radius of Giration (Rg) ranging from 200 Å at 3 h of neutralization to 160 Å at 48 h. The maximum particle size (Dmax) ranged from 650 to 550 Å was obtained from the Pair-distance Distribution Function (p(r)). SEM images showed a globular vesicular morphology with micrometric sizes. Electrical conductivity values showed a decrease between 3 and 48 h of neutralization, from 1.52 × 10−10 to 1.13 × 10−10 S/cm.