From interfacial locking to localized adaptive sliding: Temperature-driven transition in PEEK/POM heterogeneous friction

PEEK and POM are promising polymer gear materials for lightweight and low-noise transmission systems, yet their interfacial friction mechanism under temperature variation remains insufficiently understood. In this work, molecular dynamics simulations were conducted to compare PEEK-PEEK, POM-POM and PEEK-POM sliding contacts at 220–500 K, aiming to clarify the molecular origin of their temperature-dependent tribological behavior. The PEEK-POM interface exhibited a reverse deformation trend compared with the homogeneous pairs: at 220 K, its deformation length was 8.0 times that of PEEK-PEEK and 2.86 times that of POM-POM, whereas at 500 K it became lower than that of POM-POM. Meanwhile, its high shear and volumetric strain fractions increased from 2.3% to 48.6% and from 1.5% to 41.2%, respectively. Energy analyses revealed interfacial constraint release and torsional conformational activation at elevated temperatures. These findings reveal a transition from interfacial locking to localized adaptive sliding and provide molecular level insight into the temperature dependent friction mechanisms of heterogeneous polymer interfaces.