Serles Peter, Hamidinejad Mahdi, Demingos Pedro Guerra, Ma Li, Barri Nima, Taylor Hayden, Singh Chandra Veer, Park Chul B, Filleter Tobin
Department of Mechanical & Industrial Engineering, University of Toronto, 5 King's College Road, Toronto, Ontario M5S 3G8, Canada.
Department of Engineering, University of Cambridge, 17 Charles Babbage Road, Cambridge, United Kingdom, CB3 0FS.
Nano Lett. 2022 Apr 27;22(8):3356-3363. doi: 10.1021/acs.nanolett.2c00614. Epub 2022 Apr 6.
2D materials are well-known for their low-friction behavior by modifying the interfacial forces at atomic surfaces. Of the wide range of 2D materials, MXenes represent an emerging material class but their lubricating behavior has been scarcely investigated. Herein, the friction mechanisms of 2D TiCT MXenes are demonstrated which are attributed to their surface terminations. We find that TiCT MXenes do not exhibit the well-known frictional layer dependence of other 2D materials. Instead, the nanoscale lubricity of 2D MXenes is governed by the termination species resulting from synthesis. Annealing the MXenes demonstrate a 7% reduction in OH termination which translates to a 16-57% reduction of friction in agreement with DFT calculations. Finally, the stability of MXene flakes is demonstrated upon isolation from their aqueous environment. This work indicates that MXenes can provide sustainable lubricity at any thickness which makes them uniquely positioned among 2D material lubricants.
二维材料因其通过改变原子表面的界面力而具有低摩擦行为而闻名。在众多二维材料中，MXenes是一类新兴材料，但其润滑行为鲜有研究。在此，我们展示了二维TiCT MXenes的摩擦机制，这归因于它们的表面端基。我们发现，TiCT MXenes并不表现出其他二维材料所熟知的摩擦层依赖性。相反，二维MXenes的纳米级润滑性由合成产生的端基种类决定。对MXenes进行退火处理后，OH端基减少了7%，这与密度泛函理论计算结果一致，摩擦降低了16 - 57%。最后，我们证明了MXene薄片在从水环境中分离后具有稳定性。这项工作表明，MXenes在任何厚度下都能提供可持续的润滑性，这使其在二维材料润滑剂中具有独特的地位。
