Reversible colorimetric changes of a nanoporous polyaniline conducting particles system for sensing metal ions

We described reversible calorimetric changes using nanoporous polyaniline (half-reduced form: emeraldine base (EB), and fully reduced form: leucoemeraldine base (LB)) particles and transition metal ions (Ag+, Cu2+, or Cr3+) based on metal complexation. We analyzed the metal complexation capabilities of the polyaniline by UV and IR spectral changes to be used as sensing metal ions. It was demonstrated that the nature of the resulting solutions formed from the different interaction of the EB or LB system of nanoporous particles is strongly dependent on the nature of the cation metal species such as the EB or LB/metal molar ratio.