Synthesis and nonlinear optical properties of reduced graphene oxide covalently functionalized with polyaniline

Reduced graphene oxide covalently decorated with polyaniline was synthesized through a novel three step approach. Graphite oxide synthesized by a modified Hummers method, was first subjected to acylation, followed by a covalent functionalization with phenylene diamine and then it was polymerized along with aniline monomer, hence forming amide linkages between polyaniline and reduced graphene oxide. The covalent linkage formed was characterized by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. Morphology was studied by scanning electron microscopy. The hybrid showed improved nonlinear optical properties compared to the graphene oxide precursor and the pristine polyaniline. The improvement in the optical limiting performance of the hybrid is attributed to a combination of outstanding properties of graphene oxide and polyaniline, like nonlinear scattering, two photon absorption and reverse saturable absorption. (C) 2013 Elsevier Ltd. All rights reserved.