Efficacy of hierarchical pore structure in enhancing the tribological and recyclable smart lubrication performance of porous polyimide
Hongwei Ruan, Yaoming Zhang, Fuzhi Song, Qihua Wang, Chao Wang, Tingmei Wang
Abstract
Abstract Herein, a porous oil-containing material with hierarchical pore structure was successfully prepared through microtexturing large pores on the surface of porous polyimide (PPI) with single-level small pores. Compared to the conventional oil-containing material, the hierarchically porous oil-containing material exhibited high oil-content, and retained excellent mechanical properties and high oil-retention because of the synergistic effects of large pores and small pores. Furthermore, the lubricant stored in the hierarchically porous polyimide could release to the interface under thermal-and-mechano-stimuli, and the released lubricant could be reabsorbed into the hierarchically porous polyimide via the capillary-force offered by the porous channel. Based on the high oil-content and recyclable oil release/reabsorption, the hierarchically porous oil-containing polyimide exhibited excellent lubrication performance (coefficient of friction was 0.057). Furthermore, the composite could perform 1,069 cycles of smart lubrication (1 h per cycle), which significantly extended the service life of the hierarchically porous oil-containing smart lubrication material.