Polymer Brush‐Functionalized MoS2 as a Water‐Based Lubricant Additive

Abstract Water‐based lubricants have the advantages of low cost, easy cleaning, and environmental friendliness, and are suitable for various lubrication applications. However, the limited tribological properties of pure water‐based lubricants restrict their use. To improve these properties, water‐based lubrication additives can be employed. Molybdenum disulfide (MoS 2 ) is widely used in tribology because of its stability, corrosion resistance, and wear resistance, but it has poor dispersion in water. To address this, MoS 2 functionalized with poly(3‐sulfopropyl methacrylate potassium salt) (MoS 2 +PSPMA) is successfully prepared by grafting polymer brushes onto MoS 2 using ultraviolet light. The results show that MoS 2 +PSPMA exhibits significantly better dispersion stability in water compared to unmodified MoS 2 . Additionally, MoS 2 +PSPMA demonstrates superior tribological properties as a water‐based lubrication additive. During reciprocating friction, MoS 2 +PSPMA disperses effectively in water, forming a protective film on the wear surface that reduces friction. As an additive, MoS 2 +PSPMA indicates good dispersion and a low friction coefficient in water, positioning it as a promising candidate for future water‐based lubricants.