Covalently linked nanocomposites of polypyrrole with graphene: Strategic design toward optimized properties

Naiane Naidek, Aldo J. G. Zarbin, Elisa S. Orth

Index: 10.1002/pola.28944

Full Text: HTML

Abstract

ABSTRACT Graphene-based nanocomposites with conducting polymers have attracted increasing interest due to the enhanced synergistic properties, which can potentiate and broaden applications. In this context, covalent functionalization stands out as a strategic designing tool, which optimizes the interaction between the nanocomposites components. Herein, covalently linked polymeric nanocomposites were obtained between graphene derivatives and polypyrrole (Ppy) under mild routes (i.e., aqueous, room temperature). First, pyrrole was covalently functionalized on graphene oxide (GO) through stable amide bonds and further polymerization with FeCl3 led to the polymeric nanocomposites. Finally, to improve conductivity, GO was reduced using NaBH4. Similarly, analogous non-covalent nanocomposites were obtained for comparison purposes. All samples were thoroughly characterized by thermogravimetric analysis, scanning electron microscopy, and infrared and Raman spectroscopy, confirming the targeted functionalization, polymerization, and reduction processes. Moreover, the covalent link effectively enhances the interaction of the nanocomposite's components as evidenced by its improved electrochemical stability (300 cycles), compared to the non-covalent composites which loses conductivity in the initial stages. Indeed, Ppy is known for its low stability, limiting its applications. Overall, the results herein evidence that covalently linked nanocomposites can be successfully obtained with optimized electrochemical response, promising for applications as supercapacitors and artificial muscles. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018. Novel polymeric nanocomposites derived from graphene and polypyrrole have been obtained by covalently linking monomers on the graphene surface that are further polymerized, leading to a highly interconnected composite. Indeed, the challenge nowadays is to obtain conducting polymeric nanocomposites that benefit from synergistic properties, hence the proposed covalent functionalization stands out as a strategic tool to enhance properties. The approach evidences higher electrical stability for the covalently linked material, in contrast to non-covalent composites, broadening applications.