Adaptive Lubrication Enabled by Topology-Programmed Janus Microgels

Abstract Achieving stable and adaptive lubrication under dynamically varying sliding conditions remains a challenge for energy-efficient lubricating materials, as conventional colloidal lubricants fail to simultaneously regulate interfacial rheology and lubrication behavior. Herein, topology-programmed Janus microgels (JMGs) enabling adaptive lubrication with reduced frictional energy loss are proposed for metal interfaces. By tuning the hemisphere mass ratio, JMGs transform from a “snowman” to a “reverse snowman,” programmably regulating the internal single- and dual-gelator networks. The “reverse snowman” exhibits a 54.2-fold higher elastic modulus than the “snowman,” while the “snowman” achieves a minimum coefficient of friction of ∼0.12, 1.7-fold lower than that of homogeneous microgels, thereby lowering energy consumption. This synergy of boundary and rolling lubrication arises from topology asymmetry. Effective lubrication is maintained across different microgel sizes and low dispersion concentrations, enabling material-efficient adaptive lubrication. This work provides a topology-programming strategy for designing sustainable adaptive lubricating microgels, promoting energy-saving tribology with reduced material waste and environmental impact.