Cobweb-like Structural Stimuli-Responsive Composite with Oil Warehouse and Transportation System for Oil Storage and Recyclable Smart-Lubrication.

Despite recent advances in the stimuli-responsive composites for oil storage and smart lubrication, achieving the high oil storage and recyclable smart-lubrication remains a challenge. Herein, a novel cobweb-like structural system consisting of oil warehouse and transportation system was designed and prepared and it shows high capacity of oil storage and recyclable smart-lubrication. Hollow SiO2 microspheres grated of KH550 and porous polyimide (PPI) were used as oil warehouse and pipeline, respectively, to build the smart system. Because of the novel structure, the composites can keep both high oil-content and oil-retention. Applying stimuli on materials resulted in lubricants releasing on the contact surface which can reduce the friction and wear during sliding. However, removing stimuli, the capillary force induced the sucking back of lubricant into the interior of composites through interconnected small pores of PPI. On the basis of high oil storage and stimuli-responsive performance, the composites can be used for recyclable smart-lubrication. The composites showed remarkable lubricating properties (coefficient of friction 0.056 and Ws 3.55 × 10-7 mm3 N-1 m-1) when the content of KHSM (hollow silica microspheres grated of KH550 (3-Aminopropyltriethoxysilane)) was 1.5 wt % by subjecting it to macroscopic pin-on-disc friction tests. Therefore, cobweb-like structural composites with oil warehouse and transportation system hold the promise for formulating of high oil storage and recyclable smart-lubrication.