Tribological behavior of ZnS-filled polyelectrolyte multilayers

The pristine polyelectrolyte multilayers (PEMs) were prepared by layer-by-layer deposition technique. The ZnS nanoparticles were in situ-synthesized in the pristine PEMs, and the composite was denoted as ZnS-filled PEMs. The friction and wear properties of ZnS-filled PEMs were investigated on a UMT-2 against stainless steel ball. The morphologies of the wear traces were observed by scanning electron microscope. It was found that ZnS-filled PEMs exhibit higher antiwear life than unfilled ones. This should be attributed to the ZnS nanoparticles formed in the PEMs enhancing the load-carrying capacity. Moreover, the PEMs with three reaction cycles have considerably lower friction coefficient and higher antiwear life than the PEMs with six reaction cycles, that is to say, an optimum amount of ZnS nanoparticles within PEMs can improve the tribological performance greatly.