Polyaniline/graphene nanocomposite: Effect of the graphene functionalization with a long-chain fatty acid

Abstract

Polyaniline (PANI)/graphene nanocomposites are expected to be useful in several applications, such as supercapacitors, sensors, corrosion protection, and photocatalysis. The performance of the nanocomposite depended on the interaction between graphene and PANI and the good distribution of the nanomaterial in the polymer matrix. This study investigated the effect of graphene surface modification with a long-chain fatty acid on the nature of the interactions of PANI/graphene nanocomposites. Myristic acid, a long-chain fatty acid with a 13-carbon backbone, was added to the graphene surface to improve the interaction and distribution of the graphene nanoplatelets in the PANI matrix. An innovative mechanochemical route was applied to functionalize the graphene surface with the fatty acid by ball milling. Nanocomposites were prepared through the in situ synthesis of PANI on pristine and functionalized graphene surfaces. The bare and composite materials were characterized by scanning electron microscopy, X-ray diffraction, thermogravimetric analysis, ultraviolet–visible–near infrared spectroscopy, Fourier transform infrared spectroscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy. Summarily, noncovalent graphene functionalization was successfully achieved. The results indicated that the functionalized graphene acted as a template for the uniform growth of PANI. It was concluded that the nature of the interactions with PANI was different for graphene (π–π stacking) and functionalized graphene (electrostatic and hydrophobic attraction). The characterization performed showed that the graphene surface modification allowed the production of a nanocomposite with a uniform distribution, better graphene incorporation, and good electronic properties. We concluded that this nanocomposite is suitable for applications that use redox PANI properties, such as sensors and anticorrosive coatings.