1H NMR Determination of the Doping Level of Doped Polyaniline

H-1 NMR spectroscopy is an important method to obtain detailed structural information about polymers. In this study, we demonstrate the assignment of a new set of triplet peaks (sharp, equal-strength, and equidistant peaks at delta = 6.97, 7.07, and 7.17 with a coupling constant of 51.1 Hz) in H-1 NMR spectra for doped PANT, which are directly correlated with the protonation of the PANI backbone. The H/D exchange, dedoping, and redoping procedures supply the experimental proofs. Analyses show that the integral area ratio of the triplet peak is dependent on the effective doping of PANI and has a clear relationship with the conductivity. It thus provides a quantitative tool to evaluate the doping nature of PANI.