From the results presented in this paper, it appears that minor
changes in the concentration of PANI pigment in a coating formulation
can lead to a very different protective behaviour. In the
present chlorinated rubber system, the PANI concentration should
be preferably below 1 wt.% with corrosive dopant such as benzene
sulfonic acid while higher concentrations will be preferred with
PANI containing a large amount of LS anion. The latter case is well
exemplified by PANI–LS2 based formulations which showed the
best anticorrosive properties, among the concentrations investigated,
at a 3% PANI loading. LS. We also found that the sulfonated
lignin was mainly non-grafted (i.e., not covalently bonded) to PANI
chains. This opens the way to an inhibitory effect by LS dopants
released upon reduction of PANI ES to its non-conducting leuco
counterpart.