Rapid Functionalization of Graphene Oxide in Water

Polymer composites containing carbon nanoparticles have recently garnered much attention due to superb electronic, mechanical, and gas barrier properties. Graphene oxide (GO) and reduced graphene oxide (rGO) stand out among carbon nanofillers due to cost efficiency and scalability, but one hurdle preventing their widespread use is the lack of miscibility of GO and rGO platelets with polymer matrixes. The desired processability can be achieved by covalent fiinctionalization of GO and rGO, but current methods necessitate anhydrous conditions and harsh reagents. Herein, we describe the rapid covalent fiinctionalization of GO and rGO in acidic aqueous suspensions under ambient conditions using the Pinner reaction between hydroxyl groups on (r)GO and nitriles. The modified platelets are characterized by FTIR, Raman, AFM, TGA, XPS, and fourpoint probe conductivity measurements. Using this methodology, GO requires little purification and no drying after preparation and multiple grams can be functionalized with a variety of small molecule and polymer nitriles in only a couple of hours. Furthermore, functionalized platelets are isolated by centrifugation or filtration, readily giving conductive platelets with tailored solubility and functionalities for further modification.