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A porous MoS2-polyhedral oligomeric silsesquioxane (POSS) nanohybrid was prepared from octavinyl-POSS nanoparticles and MoS2 nanosheets for the first time, the structure and composition of which were confirmed by X-ray powder diffraction (XRD), Fourier-transform infrared spectra (FTIR), scanning electron microscopy (SEM), energy dispersive spectra (EDS) and thermal gravimetric analysis (TGA). As a comparison, MoS2 nanosheets, octavinyl-POSS and MoS2-POSS nanohybrid were used as lubricating additives for liquid paraffin (LP), which decreased the friction coefficients of LP by 7.8% (MoS2), 14.1% (octavinyl-POSS), and 18.8% (MoS2-POSS). Compared with MoS2 and octavinyl-POSS, the MoS2-POSS nanohybrid can be dispersed in organic solvents more homogeneously without adscititious dispersants or surfactants due to its better organic compatibilities. SEM and EDS analyses indicate that a synergistic frictional effect is responsible for the improved friction-reduction and anti-wear behavior.

A porous MoS

Monolayer or ultrathin transition metal dichalcogenides cover a wide range of atomically thin two-dimensional (2D) materials, whose fascinating properties have made them promising candidates for many applications. In this work, ultrathin MoS2 flakes were successfully exfoliated, induced by bovine serum albumin (BSA) or hemoglobin (HB), under vigorous ultra-sonication. They were used as additives for water-based lubricating systems and related investigations indicated that they could improve the friction performance and anti-wear abilities at a relatively low concentration: 0.10 wt% of additive contents can make the average friction coefficient stabilize in the range between 0.06 and 0.08, which results from the formation of a dynamic protective film on the friction surfaces. The protein-induced ultrathin MoS2 flakes are also expected to be useful for other hydrophilic lubrication systems, which possess great scientific value and promising application prospects compared with bulk or microscale lubricating additives.

Polyhedral oligomeric silsesquioxane (POSS) based nanohybrids were prepared via “thiol–ene click” reaction between vinylPOSS and alkyl mercaptan. The structure and composition of these hybrids were characterized by 1H nuclear magnetic resonance (1H NMR), thermo-gravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FT-IR). The effects of carbon chains of mercaptan and concentration variations of POSS nanohybrids on the tribological performance improvements of liquid paraffin (LP) were investigated. According to our experimental results, the optimal concentration of POSS nanohybrids in LP was 0.40 wt%, corresponding to the lowest friction coefficients of 0.099 (for OS-POSS additive) and 0.101 (for OD-POSS additive) respectively. POSS nanohybrids can achieve homogeneous dispersion in LP, while a hard, stable Si–O cage in their molecular structure provided effective wear resistance. These nanohybrids were expected to be useful for more lubricating oil systems, which possess great scientific values and promising application prospects compared with pure solid or liquid lubricating additives.