Tunable electrical conductivity and dielectric properties of triglycine sulfate-polypyrrole composite

Triglycine sulfate (TGS) crystals were grown from aqueous solution using a slow evaporation technique. Polypyrrole (PPy)/TGS composites were prepared by ex situ technique employing solvent casting method. TGS crystal showed a second-order phase transition at 49 degrees C, which confirms its ferroelectric nature. The XRD pattern of PPy/TGS composites showed the effective filler-polymer matrix interaction. The morphologies of the composites were analyzed through field emission transmission electron microscopy. A gradual increment in DC conductivity of PPy was observed with increase in temperature, revealing its semi-conducting behavior. PPy/TGS composites also demonstrated a similar trend but with drastic decrement in conductivity value, highlighting the insulating behavior of TGS. The dielectric loss of the composites was significantly lower compared to PPy. Despite low dielectric permittivity. PPy/TGS composite can be effectively utilized as memory devices due to its low dielectric loss. (C) 2012 Elsevier B.V. All rights reserved.