基于微悬臂梁技术对固液界面间横向摩擦力的检测

Lateral friction detection of solid-liquid interface based on microcantilever technology

研究固液界面上的力学行为对于界面科学和工程应用具有重要意义,如何检测液滴在材料表面的横向摩擦力一直是界面领域研究的难题之一。本文基于微悬臂梁传感技术和视觉图像分析技术,设计并搭建了一套固液横向摩擦力检测系统,将毛细管端部的弯曲程度与固液界面的相互作用力建立关系,实现对固液界面间横向摩擦力的精确测量;通过对水滴在疏水界面运动过程的检测,分析液滴运动时固液界面横向摩擦力的变化,并验证系统检测数据的准确性与可行性。结果表明,固液界面间横向摩擦力的变化与液滴体积以及表面润湿性有关,液滴体积以及材料表面润湿性的增加导致横向摩擦力的增加;液滴动态接触角的变化与其固、液、气三相接触线的运动速度有关,随着相对速度的增加,固液界面间的静摩擦力也随之增加。

The study on the mechanical behavior of solid-liquid interface is of great significance to applications in interface science and engineering.How to detect the lateral friction force of the liquid drop on the material's surface has always been one of the challenging problems in interface research.In this work,a solid-liquid lateral friction detection system is set up based on microcantilever sensing and visual image analysis technology.The system can measure the lateral friction force of the liquid interface,and the relationship between the bending of the capillary and the interaction force of the solid-liquid interface is studied.The movement process of the water droplet on the hydrophobic interface can be recorded by the visual image analysis technology.The results show that the lateral friction on the solid-liquid interface is related to the droplet volume and surface wettability.The increasing droplet volume and the surface wettability of the material lead to increasing lateral friction.The change of the dynamic contact angle of the droplet is related to the three factors.The moving speed of the contact line is further discussed.As the relative speed increases,the static friction force on the solid-liquid interface increases.