MXene-Controlled PTFE Release for Ultra-Low Friction PEEK Composites

Poly(ether-ether-ketone) (PEEK) is a key structural material in lightweight robots, yet its poor self-lubricity limits use in moving components. This study develops PEEK-based composites incorporating poly(tetra-fluoroethylene) (PTFE) as the lubricating phase and Ti₃C₂T_x MXene as transfer film mediator is designed and fabricated via hot-press sintering. Their mechanical properties are studied via a compressive test, and their tribological performances are probed upon sliding against the ZrO₂ ball with a linear reciprocating ball-on-plane configuration. By synergistically regulating the content of PTFE and MXene, the threshold content of PTFE and MXene for achieving an ultra-low friction can be obtained, which strengthens the composites and thus contributes to ultra-low wear. At an optimal PTFE content of 10 wt.%, MXene addition doubles the engineering strain, accompanied by an 11% increase in compressive strength. Meanwhile, the increased content of Ti₃C₂T_x continuously reduces the coefficient of friction to 0.060 ± 0.001, which is 26.83% lower than that of the composite without MXene, while keeping the wear rate at a low level of 10⁻⁶ mm³ N⁻¹·m⁻¹. According to the molecular dynamics simulation, the excellent anti-friction and anti-wear performance can be attributed to the controlled release of PTFE by Ti₃C₂T_x MXene, which originates from their strong interfacial bonding.