Ab initio studies of the differences in the chemical reactivity and electronic properties of polyaniline and its derivatives

The chemical reactivity and electronic properties of polyaniline (PANI) and its derivatives are systematically investigated using density functional simulations (DFT). The results indicate that carbonic acid (H2CO3) doping emeraldine base polyaniline (EB-PANI) or its derivatives are unspontaneous endothermic reactions. EB-PANI shows better chemical reactivity after the modification by different functional groups -OH and -NaSO3, the energy of reaction (Er) and energy of barrier (Ebar) are both decreased. The band gap are shows dissimilar trends by introducing different functional groups which -OH decrease and -NaSO3 increase. However, the band gap of EB-PANI and its derivatives are dramatic decrease when doping by hydrochloric acid (HCl) or H2CO3 which tend to increase the conductivity at finite temperatures. Especially, the band gap of H2CO3 doped Na-SPANI is far below the EB-PANI and OH-PANI even close to the HCl doped EB-PANI. These simulation results are helpful for further study and application of PANI and its derivatives.