Self-lubrication waterborne epoxy composite coating with amphiphilic Janus nanoparticles

Eco-friendly waterborne bonded solid lubricating coating (BSLC) has attracted increasing concern for surface protection engineering. However, the development of BSLC with outstanding comprehensive performance (lubrication, wear resistance and flexibility) remains challenging. In this study, surface-partitioned Janus nanoparticles (JNPs) was specially designed and applied to modify waterborne epoxy (EP) BSLC, in which the hydrophobic polytetrafluoroethylene (PTFE) and hydrophilic silica acted as soft side and hard side of PTFE@Silica JNPs, respectively. With unique amphipathicity, the hydrophobic PTFE can be uniformly dispersed in waterborne EP. The attained EP-JNPs composite coating with a moderate additive amount of JNPs (i.e., EP-JNPs20 wt%) has desirable lubrication and anti-wear (coefficient of friction and wear volume are about 80 % and 90 % lower than EP, respectively.). The formed PTFE tribofilms and the stiffening effect of silica lobes collaborate together to realize the outstanding self-lubrication of EP-JNPs composite coating. This drives the application of waterborne BSLC in the fields of wear-resistance coatings.