Synergistic Amination of Graphene: Molecular Dynamics and Thermodynamics

Functionalization of graphene using organic moieties constitutes an affordable way to modulate its physical and chemical properties. Finding an exact structural formula of functionalized graphene using experimental approaches is challenging. We studied in detail the thermal stability and thermodynamics of amino- and ethylamino-graphene and found a surprising synergistic effect: more amino groups stabilize functionalized graphene favoring further amination, whereas a small concentration of amino groups is unstable in many cases. The functional groups can be attached either on the same side or simultaneously on different sides of the graphene sheet. Deformation of functionalized graphene is proportional to the number of amino groups. Complete amination leading to formation of the ultimate product, Cx(NH2)x, is hindered sterically. Our study assists in the determination of the structure of chemically modified graphene and makes specific predictions that can be tested and validated experimentally.