Yan Caishan, Guan Dongshi, Wang Yin, Lai Pik-Yin, Chen Hsuan-Yi, Tong Penger
Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong.
State Key Laboratory of Nonlinear Mechanics, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, China.
Phys Rev Lett. 2024 Feb 23;132(8):084003. doi: 10.1103/PhysRevLett.132.084003.
We report direct atomic force microscopy measurements of pinning-depinning dynamics of a circular moving contact line (CL) over the rough surface of a micron-sized vertical hanging glass fiber, which intersects a liquid-air interface. The measured capillary force acting on the CL exhibits sawtoothlike fluctuations, with a linear accumulation of force of slope k (stick) followed by a sharp release of force δf, which is proportional to the CL slip length. From a thorough analysis of a large volume of the stick-slip events, we find that the local maximal force F_{c} needed for CL depinning follows the extreme value statistics and the measured δf follows the avalanche dynamics with a power law distribution in good agreement with the Alessandro-Beatrice-Bertotti-Montorsi (ABBM) model. The experiment provides an accurate statistical description of the CL dynamics at mesoscale, which has important implications to a common class of problems involving stick-slip motion in a random defect or roughness landscape.
我们报告了对圆形移动接触线（CL）在微米级垂直悬挂玻璃纤维粗糙表面上的钉扎-去钉扎动力学进行的直接原子力显微镜测量，该玻璃纤维与液-气界面相交。作用在CL上的测量毛细管力呈现出锯齿状波动，力以斜率k（粘着）线性累积，随后是力δf的急剧释放，δf与CL滑动长度成正比。通过对大量粘滑事件的深入分析，我们发现CL去钉扎所需的局部最大力Fc遵循极值统计，测量得到的δf遵循具有幂律分布的雪崩动力学，与亚历山德罗-比阿特丽斯-贝托蒂-蒙托尔斯（ABBM）模型高度吻合。该实验提供了中尺度下CL动力学的精确统计描述，这对涉及随机缺陷或粗糙度景观中粘滑运动的一类常见问题具有重要意义。
