Interaction of Graphene with Self Assembled Monolayers

Abstract

The adsorption of graphene onto solid surface is vital for the numerous device applications. In the present work, we studied interaction of graphene with chemically modified surfaces. We formed the self-assembled monolayers (SAM) of octadecanethiol (ODT), mercapto undecanoic acid (MUA) and biphenyl dithiol (BPD) onto the gold substrates. The nature of the surfaces obtained for ODT and MUA were hydrophobic and hydrophilic, respectively. The SAM of BPD yields the surface with phenyl rings having delocalized π-electrons. Due to hydrophobic nature of the graphene, it adsorbs onto the SAMs of ODT and BPD. The surface morphology of the graphene onto SAMs was studied using atomic force microscope. Due to π−π stacking interaction between the graphene and BPD molecules, graphene prefers planar adsorption onto the SAM of BPD. The hydrophobic interaction between the graphene and ODT leads to random and non-uniform adsorption of graphene onto the SAM of ODT. Surface plasmon resonance (SPR) phenomenon is extremely sensitive technique to detect minute change in dielectrics at the given interface. The adsorbed layers of the organic materials were studied using a SPR instrument.