Synthesis and temperature-sensitive lubrication behavior of PNIPAM microgels for titanium alloy

Purpose This paper aims to offeri novel nano-additives polymer microgels to precisely improve the lubrication properties of titanium alloy under different temperatures. Design/methodology/approach The surfactant-free emulsion polymerization method was used to prepare Poly(N-isoprolylacrylamide) (PNIPAM) microgels. A ball-on-disk tribometer was applied to investigated the temperature-sensitive lubrication behavior of PNIPAM microgels. Findings The results show that the as-prepared microgels are ball-like nanoparticles with the size of 50–900 nm. In addition, potassium persulfate as initiator, complete mixing technic and high sodium dodecyl sulfate (SDS) concentration contribute to the formation of microgels with small size. The tribosystem shows a lower friction coefficient with the lubrication of PNIPAM microgels as aqueous solution additives when the temperature exceeding the critical temperature. Originality/value This work reports the temperature-sensitive lubrication of PNIPAM microgels. The critical temperature of PNIPAM microgels could be regulated by the addition of SDS in the solutions. This offers an effective and facile strategy for regulation of the critical temperature of smart microgels, which is helpful for the smart lubrication in the future.