“…One of the most important applications of Polyaniline (Pani) and its derivatives is as pH sensors of different types: potentiometric [1][2][3][4][5], conductimetric [6], amperometric [7], or based on its optical properties [8][9][10]. For this reason, the knowledge of the acid dissociation constant value, of the different redox forms of Pani, is a relevant subject.…”