Robust and universal macroscale superlubricity with natural phytic acid solutions

Using superlubricants to reduce friction and wear can dramatically reduce energy consumption and economic losses in industrial production. In this paper, we report a natural and environmentally friendly lubricant based on phytic acid solution (PA-0) that can achieve robust macroscale liquid superlubrication between PDMS and glass interfaces, and the superlubrication state can be maintained for at least 13 h. Significantly, its superlubrication can also be extended to other friction pair materials, reflecting its robustness and universality as a superlubricant. The calculation of the lubricating film thickness reveals that the superlubrication realized by the PA-0 solution belongs to the mixed lubrication state that comprises boundary lubrication and hydrodynamic lubrication. These findings may advance the practical application of liquid superlubrication.