Structure and properties of polyaniline interacting with H-phosphonates

•Polyaniline base interacts with H-phosphonates and forms conductive products.•Conductivity qualitatively correlates with acidity of H-phosphonates.•Raman and EPR spectroscopies provide consistent information on polaron delocalization/charge carriers.

Polyaniline (PANI) is conducting when doped, typically with an acid. However, acids are not the only species able to dope PANI. In this study, we show that non-conducting PANI base powder interacts with dimethyl H-phosphonate (DMPH), diethyl H-phosphonate (DEPH), dibutyl H-phosphonate (DBPH) and diphenyl H-phosphonate (DPPH) and yields conducting adducts; the highest conductivity 0.23 S cm−1 is observed for DPPH. The samples were analyzed by FTIR, Raman, NMR, and EPR spectroscopies. We have shown that the doping of PANI with H-phosphonates is only partial and at least part of DEPH and DPPH molecules preserves the H-phosphonate structure, in contrast with DMPH and DBPH. We have also correlated the information on polaron delocalization and mobility obtained from Raman and EPR spectra - polarons in the PANI adduct with DEPH and DPPH have higher mobility. This paper represents a comparative study of a class of PANI-based materials and shows a connection between chain conformation of PANI and materials properties.

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