A study on surfactant modified polypyrrole nanostructures and its applications in supercapacitors

Nanocomposites of Polypyrrole (Ppy), were synthesized by chemical oxidative polymerization of pyrrole, in the presence of mono and mixed-surfactant solutions using ammonium persulfate as an oxidant and were investigated for its applications in super capacitors. The surfactants used in the experiments included anionic surfactants, sodium dodecyl sulfate (SDS) and sodium dodecylbenzenesulfonate (SDBS) and cationic surfactants, tetradecyltrimethylammonium bromide (TTAB) as well as cetyltrimethylammonium bromide (CTAB). The morphology and structure of the resulting Ppy were investigated in detail with FESEM and FTIR, respectively. The addition of anionic surfactants produced globular morphology. The results showed that the interaction between the different surfactants and the interaction between the surfactants and the polymer influenced the morphology, structure and conductivity of the resulting polymer to different degrees. Apart from these, XRD, UV-Vis spectroscopy and cyclic voltammetry (CV) were also performed to characterize the prepared composites. In comparison with the results for mono surfactant solutions, the polymerization of pyrrole in mixed-surfactant solutions shows significant changes in morphologies and electrochemical properties of Ppy. The results of CV show that the specific capacitance values of Ppy samples with anionic surfactants are greater than cationic surfactants. In case of mixed surfactants, sample with SDBS + TTAB posses highest specific capacitance of 204 Fg(-1) at scan rate 100 mVs(-1). The good electrochemical properties can be attributed to the highly porous structural advantage of the Ppy sample prepared using SDBS + TTAB. It indicates the energy holding capacity or capacitance of the prepared samples and can be utilized in sensing applications like supercapacitors.