Functionalization of Graphene Oxide by Two-Step Alkylation

A new reaction sequence for the chemical functionalization of graphene oxide (GO) consisting of the nucleophilic addition of n-butyllithium (n-BuLi) to the GO sheets and a subsequent coupling and etherification reaction of the intermediates (Bu-GO)n-Lin+ and 2-ethylhexyl bromide leading to functionalized GO is developed. The reaction is investigated. The results show that the n-Bu and 2-ethylhexyl are covalently attached to the GO sheets and many sp3 carbons are formed by addition reaction of n-BuLi to the plane of GO. After functionalization, the dispersibility of functionalized GO in ortho-dichlorobenzene (ODCB) increases significantly to 0.4 mg mL-1 and the structural integrity of the graphene sheets remained. Good electronic conductivity of the film prepared from functionlized GO (i-Octyl-Bu-GO) in ODCB is obtained after high temperature annealing.