一种基于数字图像的表面张力测量方法——悬滴法

Pendant Drop Method for Interfacial Tension Measurement

介绍了悬滴法测量表面张力的基本原理。通过重力作用下被悬挂液滴外形与表面/界面张力之间的关系,本文开发了一套基于该思想的表面张力测量装置及相应的数据处理软件。对水、无水乙醇以及两者混合物的表面张力测量及误差的分析结果显示,对于低粘度液体而言,该方法具有简便、精确、成本低廉等显著特点。

The basic principle of pendant drop method used for interfacial tension measurement is stated.It mainly links pendant drop interface profile with corresponding parameters,such as density difference,gravity and surface tension,and with hydrodynamic statics.The surface tension is then deduced according to the measured surface profile.Based on above results,a system for liquid interfacial tension measurement was developed,and correlative data processing software that can calculate the interfacial tension from edge detection manually was also incorporated.Extensive experiments were carried out to evaluate the accuracy and applicability of the proposed system in interfacial tension measurement.Experimental results of water and pure ethanol solution show that for low viscosity liquids,the pendant drop method presents significant characteristics such as simple,accuracy,low cost and good agreement with theoretical prediction,so it＇s extremely suitable for measurement in laboratory.