NaH-assisted n-doping of polyanilines with dopant cation trapping sites and their stability of n-doping state against air

- NaH-assisted n-doping of polyanilines with dopant cation trapping sites.

Polyanilines comprising aniline rings with and without a benzo-15-crown 5-ether (benzo15C5) subunit were synthesized by polycondensation initiated by ammonium persulfate. The treatment of the polymers with NaH caused deprotonation of the NH groups to yield n-doped polyanions. UV-vis spectra of the polyanions exhibited broad absorption above 700 nm corresponding to bipolaron bands. Because of n-dedoping of the polyanion, this absorption decreased gradually when the polyanion solution was exposed to air. UV-vis spectral changes suggest that the stability of the n-doping state of the polyanions increased as the content of the benzo15C5 subunit of the polymer increased. Cast films of the n-doped polymers with the benzo15C5 subunit underwent electrochemical oxidation (n-dedoping) at an unusually high potential; this factor responsible for the unusually high oxidation potential was the stabilized n-doping state that is attributed to the inclusion of Na+ in the 15C5 ring. Polymers with the benzo15C5 subunit exhibited higher stability of the n-doping state in air than those without this subunit.