  The monolayer form of CVD graphene is imposing crucial challenges in
characterization of the targeted covalent functionalization due to the low
amount of grafting moieties on the surface, which in turn hampers drawing
conclusions about reactivity-properties relationships. Due to the growing
interest in chemically modified graphene new, reliable and non-destructive
methods for its characterization are critically required. Herein we demonstrate
the use of surface-enhanced infrared absorption spectroscopy for detection of
characteristic vibration modes of species being grafted to the material either
via radical (Meerwein arylation) or nucleophilic substitution pathway on copper
foil. The phenomenon is allowed by the appropriate metal surface morphology and
no signal could have been obtained neither on Si/SiO2 substrate, nor on bare
copper. The surface of copper foil exhibit partial corrosion during the
reaction which leads to the creation of active substrate for SEIRA. The
measurements were performed using reflection-absorption and attenuated total
reflection modes with almost identical results, thus making this analytical
approach feasible, practical, non-destructive and easy to use for routine
characterization of graphene functionalization.
