Experimental measurement and theoretical prediction of the adhesion force between a single phenyl ring and graphene

Abstract

The adhesion force between a single phenyl ring and monolayer graphene was measured and calculated through experimental and theoretical methods. We used a method based on Poisson distribution statistics to extract the single-bond force between a single phenyl ring and monolayer graphene using an atomic force microscope (AFM) in water environment. The single-bond force was measured as 190.6 ± 8.1 pN, which was in good agreement with the previous research. Based on the experimental results, we proposed a theoretical model of atomic scale to elucidate the formation process of the single-bond force. The single-bond force was the maximum force in the desorption process, which was divided into two stages: processes A and B. The phenyl ring was lifted up and rotated simultaneously from the state of parallel to perpendicular to graphene in process A; it kept moving upward in the perpendicular direction in process B. The single-bond force of 190.6 pN appeared in process A when the ratio of the vertical lifting height and rotating lifting height was 0.981, which was most consistent with experimental result. Moreover, any force curve measured from experiment could be obtained by fitting the single-bond force curve calculated from theory.