Abstract：
Two-dimensional covalent organic frameworks (2D COFs) are an emerging class of crystalline porous materials formed through covalent bonds between organic building blocks. COFs uniquely combine a large surface area, an excellent stability, numerous abundant active sites, and tunable functionalities, thus making them highly attractive for numerous applications. Especially, their abundant active sites and weak interlayer interaction make these materials promising candidates for tribological research. Recently, notable attention has been paid to COFs as lubricant additives due to their excellent tribological performance. Our review aims at critically summarizing the state-of-art developments of 2D COFs in tribology. We discuss their structural and functional design principles, as well as synthetic strategies with a special focus on tribology. The generation of COF thin films is also assessed in detail, which can alleviate their most challenging drawbacks for this application. Subsequently, we analyze the existing state-of-the-art regarding the usage of COFs as lubricant additives, self-lubrication composite coatings, and solid lubricants at the nanoscale. Finally, critical challenges and future trends of 2D COFs in tribology are outlined to initiate and boost new research activities in this exciting field.
摘要：
二维共价有机框架（2DCOF）是一类新兴的结晶多孔材料，通过有机结构单元之间的共价键形成。COF独特地结合了巨大的表面积，良好的稳定性,大量的活跃位点，和可调功能，因此，它们对许多应用具有很高的吸引力。尤其是,它们丰富的活性位点和弱的层间相互作用使这些材料有希望用于摩擦学研究。最近,由于其优异的摩擦学性能，COFs作为润滑剂添加剂受到了广泛的关注。我们的评论旨在批判性地总结2DCOF在摩擦学中的最新发展。我们讨论了它们的结构和功能设计原则，以及特别关注摩擦学的合成策略。还详细评估了COF薄膜的生成，这可以减轻他们对这个应用程序最具挑战性的缺点。随后，我们分析了现有的关于使用COF作为润滑剂添加剂的最新技术，自润滑复合涂层，和纳米级的固体润滑剂。最后,概述了摩擦学中2DCOF的关键挑战和未来趋势，以启动和促进这个令人兴奋的领域的新研究活动。
