3D printing of PTFE-filled polyimide for programmable lubricating in the region where lubrication is needed

Three-dimensional (3D) target-region-lubrication printing of photosensitive polyimide (PSPI) filled with polytetrafluoroethylene (PTFE), i.e., PSPI-PTFE, with excellent tribological properties for self-lubricating devices was realized by digital light processing of PSPI-PTFE ink and thermal post-treatment. The 3D-printed PSPI-PTFE composites exhibited the friction coefficients and wear rates sharply reduced by 88% and 98%, respectively, and good mechanical properties, thermal stability and interlayer bonding as well. Importantly, the surfaces with lubricating only in regions where needed were readily realized due to the layer-by-layer manufacturing manner of 3D printing. As proof-of-concept, a target-region-lubricating bearing was demonstrated successfully, which run stably with a speed ranged from 60 to 180 rpm/min, indicating that the 3D-printed PSPI-PTFE composites are suitable for fabricating devices with complex and special shapes.