Intercalated polyaniline nanosheets prepared from lyotropic liquid crystalline solutions and their capacitive performance

Abstract

Intercalated polyaniline (PANI) nanosheets, supported by sodium dodecyl sulfate (SDS), have been prepared in one step from discotic nematic lyotropic liquid crystal (LLC) solutions. The inter-lamellar distance was observed to be dependent strongly on the stirring situation during the polymerization: an average distance of 3.4 nm is favorable for samples with and without stirring during the preparation, while a shorter one of 1.4 nm is preferable when the system was stirred only during the period of the addition of ammonium persulfate (APS). Interestingly, all UV–vis, XPS, TGA and elemental analysis experiments demonstrate clearly that the PANIs prepared in this way were in partially doped states, although all these reactions were carried out at non-acidic conditions. Such phenomenon can be attributed to the doping process induced by dodecyl sulfuric acid, which was produced in situ during the polymerization. Furthermore, all our PANIs exhibit high specific capacitance in compared with other chemically prepared systems. In particularly, superior capacitance retention propriety (as high as 86.7% in a current density of 0.4–4.0 A g −1) can be available for PANI prepared with stirring all the time, indicating its great potential to provide high power density. In short, our experiments indicate that the intercalated nanosheet structure at molecular scale is of great benefit in improving the supercapacitive performance of the corresponding electrode material in supercapacitors.