Functionality of TERGO Powders during the Synthesis of PANI-Based Composites for Electrical Devices

Abstract

In this work, hybrid composites were prepared using polyaniline (PANI) and electrochemically reduced graphene oxide (ERGO) by in situ polymerization. ERGO powders were obtained by a two-way route, Hummer's method, and one-step potential (−2 V) followed by annealing process at 400°C (TERGO powders): different quantities of TERGO fine particles (10, 20, and 30 wt%) were added to the in situ PANI polymerization in order to produce the hybrid composites. The morphology and structure of the PANI/TERGO compounds were characterized by Raman spectroscopy, ultraviolet-visible spectroscopy (UV-Vis), X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Thermal treatment of ERGO powders pointed out high-defect surfaces with a wrinkle-type morphology (I D /I G ratio~0.90). The emeraldine phase of PANI was obtained with a maximum value of 61%, which decreases with the amount of TERGO powders. It is also seen that composites displayed a combined morphology between PANI matrix and TERGO powders, confirming a physical interaction between both morphologies. The amount of TERGO particles into the polymeric matrix also modifies the sample microstructure from a semispherical shape to extend sheets, where PANI is sandwiched between TERGO layers. Electrical conductivity of composites slightly increases independent of the TERGO amount (30 S/m and 39 S/m) due to the rough TERGO surface that conditioned the homogeneous nucleation of a large amount of polymer (PANI) reducing the area to move the electrical charge.