Reactive molecular dynamics study of frictional behavior of PTFE in ultra-low temperature LO2 environments

This study employs reactive molecular dynamics (ReaxFF MD) simulations to investigate the tribological mechanisms of polytetrafluoroethylene (PTFE) under a liquid oxygen (LO2) environment. By comparatively analyzing the frictional behavior of systems with and without LO2 at 51 K, 78 K, and 100 K, the cooling and lubrication mechanisms of LO2 are elucidated. The results reveal that LO2 significantly reduces the temperature of both the friction pairs and the PTFE, achieving maximum reductions of 16.78 % and 46.86 %, respectively, at 78 K environment. Concurrently, LO2 effectively diminishes both the friction force and its fluctuations through the formation of a Fe-O lubricating film, thereby mitigating interfacial adhesion and shear resistance.