Graphene films with high hydrophobic and adhesive performance were fabricated via two simple steps: chemical exfoliation of natural flake graphite following redox, and film formation by suction filtration without any chemical modification. Irregularly stacked multilayer graphene nanosheets comprised the microstructure, whereas folding and agglomeration of graphene nanoflakes with few layers comprised the nanostructure. The films also showed remarkable surface wettability and reversible transition from hydrophobicity to hydrophilicity via periodic alternation of ultraviolet irradiation and air storage. Based on Wenzel's theory and adsorption dynamics, an optimum mechanism is proposed for the surface wettability behavior. On the one hand, the film microstructure and nanostructure enhance the graphene surface hydrophobicity. On the other hand, the capillary force is maximized by the nanostructure such that water fills the grooves of the rough solid surface. This result is a strong interaction between water and the film surface giving highly adhesive property to the films. The highly hydrophobic and adhesive performance of the graphene films could be useful in the device and biomaterials application.

The novel graphene–C60 hybrid films have been fabricated successfully on silicon surfaces by a multistep self-assembly process, and showed synergistic effects beyond individual performance in micro/nano-tribological behaviors. It is expected that the graphene–C60 hybrid films may find wide applications as high performance lubricating films in MEMS.

Melt lubricants have been regarded as an effective class to deliver lubrication on moving mechanical contacts at extreme temperatures. Among the elementary constituents, alkali elements play a critical role in governing the physical–chemical characteristics of the lubricant despite the obscurity regarding their intrinsic roles on the rubbing interfaces. The present study attempts to unfold the effects of sodium on the tribological responses of mating steel pair under borate melt lubrication. It has been found that the involvement of Na inspires a total reversal in lubricating potentials of the lone B₂O₃ melt manifested by remarkable friction reduction, wear inhibition and prolonged load-bearing capacity. These exceptional performances are attributed to the accretion of nanothin Na layers on the contact interfaces. The interfacial occurrences are interpreted from a physico-chemistry perspective while the influences of surface microstructure are also discussed in detail. Multiple characterizations are employed to thoroughly examine the sliding interfaces in multi-dimensions including Scanning Electron Microscopy (SEM), Scanning Transmission Electron Microscopy (STEM) and Atomic Force Microscopy (AFM). In addition, chemical fingerprints of relevant elements are determined by Energy Dispersive Spectroscopy (EDS) and Electron Loss Energy Spectroscopy (EELS).