Mechanical exfoliation is a widely used method to isolate high quality graphene layers from bulk graphite. In our recent experiments, some ordered microstructures, consisting of a periodic alternation of kinks and stripes, were observed in thin graph
ite flakes that were mechanically peeled from highly oriented pyrolytic graphite (HOPG). A theoretical model is presented in this paper to understand the formation of such ordered microstructures, based on elastic buckling of a graphite flake being subjected to a bending moment. The width of the stripes predicted from this model agrees reasonably well with our experimental measurements.
Reported values (0.2 MPa ~ 7.0 GPa) of the interlayer shear strength (ISS) of graphite are very dispersed. The main challenge to obtain a reliable value of ISS is the lack of precise experimental methods. Here we present a novel experimental approach
to measure the ISS, and obtain the value as 0.14 GPa. Our result can serve as an important basis for understanding mechanical behavior of graphite or graphene-based materials.
Through experimental study, we reveal superlubricity as the mechanism of self-retracting motion of micrometer sized graphite flakes on graphite platforms by correlating respectively the lock-up or self-retraction states with the commensurate or incom
mensurate contacts. We show that the scale-dependent loss of self-retractability is caused by generation of contact interfacial defects. A HOPG structure is also proposed to understand our experimental observations, particularly in term of the polycrystal structure. The realisation of the superlubricity in micrometer scale in our experiments will have impact in the design and fabrication of micro/nanoelectromechanical systems based on graphitic materials.
Despite interlayer binding energy is one of the most important material properties for graphite, there is still lacking report on its direct experimental determination. In this paper, we present a novel experimental method to directly measure the int
erlayer binding energy of highly oriented pyrolytic graphite (HOPG). The obtained values of the binding energy are 0.27($pm $0.02)J/m$^{2}$, which can serve as a benchmark for other theoretical and experimental works.
