Song Qingrui, Chen Tianci, Sun Wei, Huang Mingjian, Guo Yuhang, Jiao Yunlong, Liu Kun, Ye Jiaxin
Hefei University of Technology, Hefei, Anhui, China.
Shandong University of Science and Technology-Taian Campus, Taian, Shandong, China.
J R Soc Interface. 2025 Mar;22(224):20240751. doi: 10.1098/rsif.2024.0751. Epub 2025 Mar 12.
The lateral moving resistance of a liquid droplet on a solid surface generally increases with velocity and is dominated by the non-viscous wetting line friction. Many superhydrophobic man-made and biological surfaces have minimal, nevertheless speed-sensitive, water droplet friction, limiting their potential to reduce drag at high speeds in natural situations. Using an surface force apparatus, we demonstrated low and remarkably speed-insensitive (over 300-fold) water bridge sliding friction on a goose feather vane. Detailed analyses suggest a dominant, hidden energy dissipation channel probably related to the deformation and elastic recovery of feather's characteristic metamaterial-like structure, which also results in feather's speed insensitive (from 0.1 to 1 mm s) ultra-low dry sliding friction coefficient observed in this study (approx. 0.07). The new insights gained have the potential to motivate novel approaches to the design of all-weather and speed-insensitive low-friction surfaces with practical applications in aviation and lubrication technology.
液滴在固体表面上的侧向移动阻力通常随速度增加，并且主要由非粘性的湿润线摩擦力主导。许多超疏水的人造和生物表面具有最小的、但对速度敏感的水滴摩擦力，这限制了它们在自然环境中高速时降低阻力的潜力。使用表面力装置，我们证明了在鹅毛羽片上水桥滑动摩擦很低且对速度不敏感（超过300倍）。详细分析表明，一个主要的、隐藏的能量耗散通道可能与羽毛独特的类超材料结构的变形和弹性恢复有关，这也导致了本研究中观察到的羽毛对速度不敏感（从0.1到1毫米/秒）的超低干滑动摩擦系数（约为0.07）。所获得的新见解有可能推动设计全天候和对速度不敏感的低摩擦表面的新方法，在航空和润滑技术中有实际应用。
