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December 2006

Measuring Surface Tension with DROPimage Advanced
There are several methods that can be used to measure surface tension. Years ago ramé-hart manufactured a tensiometer which used the Wilhelmy plate method. This method, in its day, was useful but it relied on the precise measurement of force exerted by a surface on a solid. Another traditional method is the Du Noüy Ring method. This requires the measurement of the maximum force required to pull a ring from a surface. The wetting properties of the solid interface have little impact on the resulting measurement. At ramé-hart we have found significant challenges producing hardware that can be used to gather meaningful data with these legacy methods. Additionally these methods are very time consuming and have extensive setup and procedures. Thus we are currently focused solely on the Pendant drop method using drop shape analysis. Our DROPimage Advanced software supports both surface tension as well as interfacial tension studies using this method.

In the video below, we measure the surface tension of Decalin in air. The solid interface is teflon (the needle of the dispensing system). Ten measurements are taken with two seconds delay between measurements. This shows how fast and easy it is to collect valuable surface tension data, with minimal setup time, using ramé-hart Model 500 Goniometer with DROPimage Advanced v2.0. If you have any problem launching this video from within your email, click here to watch: Watch Video.


Season's Greetings
We wish to extend a warm Season's Greetings during this festive time of year. Thanks to you and all of our loyal customers, we had an excellent year -- and hoping you did to. Happy New Year to you and your kin from all of us at ramé-hart instrument co.


Carl Clegg
Director of Sales
Phone 973-448-0305
Contact us