Deep eutectic solvents show promise as greener lubricants

A new review says deep eutectic solvents could help cut friction, wear and energy losses in machinery while avoiding many drawbacks of conventional lubricants. The paper outlines current progress, key mechanisms and the main barriers to using DES-based lubricants at scale.

Why it matters: - Friction and wear in machinery drive equipment failure, energy use and resource waste. - Conventional mineral oils and synthetic lubricants face limits tied to pollution, volatility, potential toxicity and weak performance in extreme conditions. - Deep eutectic solvents could support greener, higher-performance lubrication systems for advanced manufacturing. - The review argues DES-based lubricants may help extend component life and improve sustainability in mechanical systems.

What happened: - Researchers published a review on deep eutectic solvents in tribology, focused on recent advances and future directions. - The paper summarizes DES classification, preparation methods, characterization techniques and tribological applications. - The review covers DES use as liquid lubricants, additives, eutectogel lubricants and other DES-containing materials. - The article is identified by DOI 10.3724/trad-20260004.

The details: - DESs are formed through hydrogen bonding between hydrogen bond acceptors and hydrogen bond donors. - DESs are drawing interest because they are easy to prepare, low in volatility and tunable in physical and chemical properties. - Studies cited in the review show DESs can work as lubricants, additives and building blocks for advanced lubrication materials. - The review highlights key tribology mechanisms, including hydrogen-bond network formation and evolution, interfacial adsorption and tribochemical reactions during friction. - The paper also examines factors that influence lubrication efficiency and the constraints on practical deployment. - Funding came from the Strategic Priority Research Program of the Chinese Academy of Sciences, the Key Research and Development Program of Gansu Province, CAS “Light of West China” Program, Gansu Province Science and Technology Plan, and the Excellent Doctoral Project of the Natural Science Foundation of Gansu. - A. Rosenkranz also received support from ANID-Chile through Fondecyt Regular 1220331, Fondequip EQM190057 and the Millennium Science Initiative Program NCN_2023_007.

Between the lines: - The review frames DES research as part of a broader shift toward sustainable materials in high-load, high-speed manufacturing. - The biggest barriers are not just performance, but also environmental compatibility, molecular-level understanding and scale-up. - That means the field still needs more data linking DES chemistry to real-world tribological behavior. - The paper positions interface science as central to turning DESs from promising candidates into practical lubricants.

What's next: - Future work will likely focus on improving molecular design, testing environmental compatibility and clarifying lubrication mechanisms. - The review points to the need for engineering studies that can translate DES performance into large-scale applications. - Further progress could expand DES use in sustainable lubrication technologies for advanced mechanical systems.

The bottom line: - DESs are emerging as a credible route to cleaner, more adaptable lubrication, but practical adoption will depend on better mechanistic understanding and engineering validation.