Tribological properties of superamphiphobic PPS/PTFE composite coating in the oilfield produced water

A simple spraying technique was applied to manufacture superamphiphobic polyphenylene sulfide (PPS)-based coating by nano/micro-structural design and modification with the lowest surface energy groups (-CF2-). The amphiphobic properties of PPS/polytetrafluoroethylene (PTFE), pure PPS and commercial coatings were comparatively studied. The tribological properties of these three coatings in the oilfield produced water were also investigated. Results indicated that the contact angles of water, crude oil and oilfield produced water on PPS/PTFE coating reached up to 172°, 151° and 168°, respectively, showing excellent superamphiphobic property. The wear resistance of PPS/PTFE coating was 49.1 and 89.1 times higher, respectively, than that of pure PPS and commercial coatings. The worn and counterpart surfaces were investigated by scanning electron microscopy (SEM), which revealed fatigue and abrasive wear behaviors for pure PPS coating and slight abrasive wear behavior for PPS/PTFE coating. In particular the surface of PPS/PTFE coating possessed “surface texture-like effect”, which captured debris to reduce furrows and hold oilfield produced water to facilitate formation of mixed film lubrication. Hence it contributed to the improvement of tribological properties. Besides, the effect of oilfield produced water on the tribological behaviors of PPS-based coatings is discussed.