While flow-induced voltage over a graphene layer has been reported, its origin remains unclear. In our previous study, we suggested different mechanisms for different experimental configurations: phonon dragging effect for the parallel alignment and an enhanced out-of-plane phonon mode for the perpendicular alignment (Appl. Phys. Lett. 102:063116, 2011). In order to further examine the origin of flow-induced voltage, we introduced a transverse flow component by integrating staggered herringbone grooves in the microchannel. We found that the flow-induced voltage decreased significantly in the presence of herringbone grooves in both parallel and perpendicular alignments. These results support our previous interpretation.

We report a superstrong adhesive of monolayer graphene by modified anodic bonding. In this bonding, graphene plays the role of a superstrong and ultra-thin adhesive between SiO₂ and glass substrates. As a result, monolayer graphene presented a strong adhesion energy of 1.4 J m⁻² about 310% that of van der Waals bonding (0.45 J m⁻²) to SiO₂ and glass substrates. This flexible solid state graphene adhesive can tremendously decrease the adhesive thickness from about several tens of μm to 0.34 nm for epoxy or glue at the desired bonding area. As plausible causes of this superstrong adhesion, we suggest conformal contact with the rough surface of substrates and generation of C–O chemical bonding between graphene and the substrate due to the bonding process, and characterized these properties using optical microscopy, atomic force microscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy.