Thi Quoc Huy, Man Ping, Liu Haijun, Huang Lingli, Chen Xin, Lee Chun-Sing, Zhao Jiong, Deng Qingming, Saeed Saba, Ly Thuc Hue
Department of Chemistry and Center of Super-Diamond & Advanced Films (COSDAF), City University of Hong Kong, Kowloon, Hong Kong, China.
City University of Hong Kong Shenzhen Research Institute, Shenzhen 518000, China.
Nano Lett. 2023 Feb 22;23(4):1379-1385. doi: 10.1021/acs.nanolett.2c04573. Epub 2023 Feb 10.
Low temperature and high humidity conditions significantly degrade the performance of solid-state lubricants consisting of van der Waals (vdW) atomic layers, owing to the liquid water layer attached/intercalated to the vdW layers, which greatly enhances the interlayer friction. However, using low temperature atomic force microscopy (AFM) and friction force microscopy (FFM), we unveil the unexpected ultralow friction between two-dimensional (2D) ice, a solid phase of water confined to the 2D space, and the 2D molybdenum disulfides (MoS). The friction of MoS and 2D ice is reduced by more than 30% as compared to bare MoS and the rigid surface. The phase transition of liquid water into 2D ice under mechanical compression has also been observed. These new findings can be applied as novel frictionless water/ice transport technology in nanofluidic systems and promising high performance lubricants for operating in low temperature and high humidity environments.
低温高湿条件会显著降低由范德华（vdW）原子层构成的固态润滑剂的性能，这是由于附着/插入到vdW层间的液态水层极大地增强了层间摩擦力。然而，通过低温原子力显微镜（AFM）和摩擦力显微镜（FFM），我们揭示了二维（2D）冰（一种局限于二维空间的水的固相）与二维二硫化钼（MoS）之间意外的超低摩擦力。与裸露的MoS和刚性表面相比，MoS与2D冰之间的摩擦力降低了30%以上。还观察到了液态水在机械压缩下向2D冰的相变。这些新发现可应用于纳米流体系统中的新型无摩擦水/冰传输技术，以及有望在低温高湿环境中运行的高性能润滑剂。
