This work presents the corrosion protection behaviour of mild steel in neutral saline conditions (salt
spray/immersion) by using coatings based on chlorinated rubber and benzene-sulfonate (BS) or lignosulfonate
(LS)–doped polyaniline (PANI). Standardized accelerated (salt spray) and immersion tests were
performed to assess the protective performance of the coatings. Analysis and interpretation of the experimental
data (i.e., EIS, potentiodynamic data and visual observations) showed that both PANI–BS and
PANI–LS inhibit corrosion of painted steel exposed to a 3.5% NaCl solution. Among the tested concentrations
(0.5, 1.5 and 3 wt.%), the greatest inhibition was observed at low concentration of PANI–BS (0.5%).
Samples with higher PANI–BS loadings (1.5 and 3%) appear severely corroded after 560 h of salt spray
exposure, which was related to the release of corrosive benzene sulfonic acid. On the contrary, the coatings
with lignosulfonate doped PANI performed well both in the salt spray and immersion tests, especially
at the highest PANI concentrations (1.5 or 3%). With regard to the healing properties, PANI–LS with the
lowest conductivity (1 S cm−1) performed the best.