Steady superlubricity achieved by epoxy resin composite coatings containing polydimethylsiloxane

Epoxy resin (EP) coatings have been widely applied in the field of surface protection engineering due to their high adhesion and good corrosion resistance, but the high friction and low wear resistance of pure EP coatings restrain their service life. Developing superior EP coatings with superlubricity and good antiwear performance is extensively desirable but remains to be a challenge yet. Here we for the first time report a superlubricious epoxy resin composite coating containing polydimethylsiloxane, PDMS (EP/PDMS) prepared by a facile solvent evaporation method. The PDMS was found to self-aggregate into nanoparticles in the epoxy resin matrix and leaded to the enhancement of tensile toughness of the epoxy resin coatings. The composite EP coatings con-taining PDMS performed steady superlubricity and high wear resistance when sliding against different bearing materials. Especially, an exceptionally and stable low friction coefficient of 0.007 was achieved by rotationally rubbing on the EP composite coating with a small content of 3.0 wt% against silicon nitride (Si3N4) ball in ambient air with a high relative humidity of 70 %, and the average wear rate of the EP/PDMS composite coating was as low as 2.76 x 10-7 mm3/N.m in spite of its low hardness.

Automated summary

This study reports the development of a superlubricious epoxy resin composite coating (EP/PDMS) containing polydimethylsiloxane (PDMS) for the first time. PDMS self-aggregated into nanoparticles in the epoxy resin matrix, enhancing the tensile toughness of the coatings. The EP/PDMS composite coatings exhibited stable superlubricity and high wear resistance when sliding against different bearing materials. Remarkably, under ambient air with a high relative humidity of 70%, the EP composite coating with a small content of PDMS (3.0 wt%) achieved an exceptionally low friction coefficient of 0.007, and the average wear rate of the EP/PDMS composite coating was as low as 2.76 x 10-7 mm3/N.m despite its low hardness.