One of the accurate methods for measuring the surface tension of liquids and interfacial tension between two immiscible liquids is pendant drop method. In pendant drop method, the liquid drop is hanged from a needle and surface tension is measured using the ADSA (axisymmetric drop shape analysis) algorithm method.
The surface tension results are normally affected by the needle outer diameter. To find the optimum range of the needle OD (mm), you may use Jikan’s online needle diameter calculator.
This calculator is recommended for pendant drop module of Jikan CAG-10, CAG-20 SE, and CAG-20 PE devices or any other commercial device for measuring the surface tension and interfacial tension.
Needle Size Calculator for Pendant Drop Method (Surface Tension Measurement)