LAUSR

We analyzed ionic processes within polypyrrole (PPy) covalently attached to graphene, multiwalled carbon nanotubes (MWCNTs), and single-walled carbon nanohorns (SWCNHs), operating in aqueous and hydrogel electrolytes that contain KCl, NaCl, LiCl, KBr, NaBr, and LiBr salts. Computational studies were carried out for a five-membered PPy chain with a single charged pyrrole using molecular mechanics (MMFFaq) and density functional theory (DFT B3LYP/6-31G). The analysis revealed that cation coadsorption (and corresponding doping of anions) occurs during oxidation of the polymer for potassium and sodium halides, but not for lithium salts. Electro-gravimetric analysis carried out by an electrochemical quartz crystal microbalance confirmed the cation coadsorption on the oxidized polymer in KCl. The highest ion mobility measured for several carbon-grafted PPy composites was found for MWCNT-grafted-PPy in liquid electrolytes. The ionic mobilities for the same materials embedded in a hydrogel electrolyte were compar...