Innovative Ionic Liquids as friction reducers and antiwear additives for advanced lubricants

In recent decades, hydrophobic ionic liquids (ILs) have attracted increasing interest as innovative solutions for industrial applications. This project focuses on the design and synthesis of ILs for tribological applications, aiming to develop new additives capable of reducing friction and wear. The synthetic strategies were developed with an industrial scale-up perspective, prioritizing simple procedures, cost-effective materials, and high efficiency. Starting materials were carefully selected from biobased compounds, industrial by-products, and low-toxicity substances, also including commonly used lubricant additives to achieve multifunctionality. The synthesized molecules were structurally characterized by FTIR and NMR spectroscopy, while their thermal behavior and stability were evaluated using TGA and DSC analyses. Hydrophobicity was investigated through more than 1000 solubility tests in various base oils. Tribological results showed excellent friction-reducing properties in MTM tests, with low coefficients of friction, along with a significant reduction in wear observed in four-ball tests. Promising performance was also achieved as extreme pressure additives in SRV FZG simulations. This study demonstrates the possibility of tuning the chemical structure of ionic liquids to obtain sustainable, high-performance additives suitable for industrial applications and advanced lubrication systems.