An Ecofriendly\nDesign for Superhydrophilic Natural\nDeep Eutectic Solvent Lubricants and Their Excellent Interfacial Behavior

The need for low-viscosity and sustainable lubricants\nhas always\nbeen urgent for the application of complex materials and the improvement\nof machining accuracy requirements. As a kind of lubricating material\nwith the characteristics of easy preparation and designable structure,\ndeep eutectic solvent (DES) shows excellent performance controllability\nand good application potential. Herein, a series of phosphate menthol\nDESs (P-DL) were designed and prepared as high-performance lubricants.\nThe results of their physicochemical properties show that the synthesized\nDESs exhibit low viscosity and superhydrophilicity, providing more\nefficient adsorption and interfacial self-assembly behavior. Additionally,\nenhanced corrosion resistance and thermal stability are conducive\nto their chemical stability during shearing. In terms of tribological\nproperties, P-DL exhibits optimal friction-reducing and antiwear properties,\nalong with load-bearing performance. More importantly, excellent lubrication\nstability can be obtained even under more stringent and diverse test\nconditions, indicating the universality and great engineering application\npotential of these materials as sustainable lubricants. More hydrogen\nbond donors, longer alkyl chains, and suitable branched structures\nhave a positive effect concerning the comprehensive function. Besides,\nthe synergistic effect of superhydrophilicity, polar adsorption, and\ntribochemical reaction is the key factor for the robust lubrication\nperformance. In addition, easy preparation, high-performance, and\nsustainability all provide great application potential for these lubricants.\nMeanwhile, this chemically designed lubricant optimization strategy\nwith adjustable performance also provides theoretical guidance for\nthe development and enrichment of sustainable lubrication technology.