In PANI-EB, the strongest IRAV absorption peaks are at the wavelength between 5 to 10 μm . These peaks are assigned to ring stretching, protonated imine and amine, C-H/C-N bond vibrations, and structural disorders (Supplementary Table and Fig. ). Complex permittivity of EB in Fig. is derived from Kramer-Kronig transformation of ε ) from fitting the ellipsometer data in Fig. , to account for small features caused by both polarons and disorders.