Water‐soluble graphene oxides grafted by polyanilines

Abstract The treatment of graphene oxide having 4‐aminophenyl groups (GO‐AP) with (NH₄)₂S₂O₈ yielded an ammonium radical cation (GO‐AP^.+). The radical polymerization of N‐(4‐sulfopropyl)aniline (ANPrSO₃H) and copolymerization of ANPrSO₃H with aniline (AN) in the presence of GO‐AP^.+ yielded water‐soluble GO composites that were grafted with poly(N‐(4‐sulfopropyl)aniline) and poly(N‐(4‐sulfopropyl)aniline‐co‐aniline), namely, GO‐AP‐PANPrSO₃H and GO‐AP‐PAN/PANPrSO₃H, respectively. The formation of the composites consisted of GO, PAN, and PANPrSO₃H chains that were bonded to the amino group of GO‐AP, confirmed by Raman spectroscopy, differential scanning calorimetry, and scanning electron microscopy analyses. The UV‐vis measurements suggested that the polymer chains of the composites were self‐doped by the sulfonic acid group and de‐doped by sodium sulfonation. The composites exhibited photoluminescence resulting from the polymer chain and GO depending on the excitation wavelength. They underwent electrochemical oxidation of the polymer backbone and reduction of the carbonyl groups.