  Components of technical systems and devices often require self-lubricating
properties, which are implemented by means of dry lubricants. However,
continuous lubricant coatings on the components' surfaces often suffer from
poor adhesion, delamination and crack propagation. The replacement of
continuous coatings with dense ordered arrays of microparticles consisting of
dry lubricants may overcome these drawbacks. Using the well-established solid
lubricant MoS2 as model system, we demonstrate that the sliding capability of
polymeric monoliths can be significantly enhanced by integration of arrays of
micron-sized dry lubricant microparticles into their contact surfaces. To
synthesize the MoS2 microparticle arrays, we first prepared ordered hexagonal
arrays of ammonium tetrathiomolybdate (ATM) microparticles on Si wafers by
molding against poly(dimethylsiloxane) templates followed by high-temperature
conversion of the ATM microparticles into MoS2 microparticles under Ar/H2
atmosphere in the presence of elemental sulfur. Finally, the obtained
large-scale hexagonal MoS2 microparticle arrays were transferred to the
surfaces of polymer monoliths under conservation of the array ordering.
Self-lubrication of components of technical systems by incorporation of dry
lubricant microparticle arrays into their contact surfaces is an example for
overcoming the drawbacks of continuous functional coatings by replacing them
with microparticle arrays.
