Developing an Organic-Inorganic Hybrid Material as Oil-Based Lubricant Additive

Abstract

Nano-additives offer a promising way to reduce friction and wear. Herein, an organic-inorganic hybrid material composed of MXene quantum dots (MQDs) and cetyl trimethylammonium bromide decorated covalent organic frameworks (CNUS-2) is successfully constructed by an electrostatic self-assembly strategy. The combination of MQDs and CNUS-2 not only increases the interlayer spacing of NUS-2 but also mitigates the self-aggregation of MQDs, maximizing the advantages of their intrinsic characteristics. Benefitting from the synergistic lubrication effect of zero-dimensional MQDs and two-dimensional NUS-2, the improved lubricity and interfacial bonding ability are realized. In addition, the relative slip between CNUS-2@MQDs sheets can reduce friction and anti-wear. As expected, different levels of CNUS-2@MQDs effectively boost the tribological properties. The friction coefficient (COF) (0.097) and the wear volume (1.48×105 μm3) of PAO-10 oil are reduced by 46.7% and 92.6% after introducing 3.0 wt% CNUS-2@MQDs nanocomposite. Furthermore, the abundant oxygen-containing functional groups in CNUS-2 can accelerate the formation of adsorption and tribochemical reaction films, while the MQDs can repair worn surface, achieving superior lubrication performance under variable load, temperature, and frequency conditions. This work not only effectively improves the lubrication performance by developing a unique CNUS-2@MQDs nanocomposite, but also affords a reference for designing novel lubricant additive.

Keywords: organic-inorganic hybrid material, MXene Quantum dots, covalent organic frameworks, electrostatically self-assemble, synergistic lubrication