Surface free energy is measured to get better understanding of the chemical properties of your surface. Surface free energy measurement is easily done with the help of the modern instruments available. By following the three steps described below, you get valuable information on your surface in matter of minutes.
Surface free energy is calculated through contact angle measurements. You need to measure the contact angle with at least two different probe liquids depending on the surface free energy theory you are using. Water and di-iodomethane are the most often used probe liquids. With current instruments available, it is possible to have two disposable dispensers connect to the instrument at the same time. This allows you to fill the two probe liquids into the dispenser tips and do the measurement completely automatically.
Contact angle measurements for surface free energy calculations are done the same way as a regular contact angle measurement. Since at least two liquids are needed, it is beneficial to have automated dispensing as well as automated sample stages. This gives you a possibility to program the measurements so that several contact angle measurements with two different liquids can be done with one click of a start button.
The modern instruments available can calculate the surface free energy results simultaneously as the contact angle measurements are done. The results are calculated and presented for all available surface free energy theories if the properties of the probe liquids are given. The results are stored in the result database for further analysis.
To hear more about surface free energy and see the measurement in practice, please watch the short webinar through the link below.
How to measure surface free energy in practice? WatchShort webinar
One of the commonly used surface free energy theories is called Acid - base or Van Oss-Chaudhury-Good method according to its inventors.
Surface free energy can be considered as the surface tension of a solid. Surface free energy is calculated through the contact angle measurements. By knowing the surface free energy of the solid, one can predict the behavior of any liquid on the surface.
OWRK is one of the most used surface free energy theories. It divides the interfacial interactions into two parts; polar and dispersive.
You might find it confusing when seeing all the different methods for surface free energy calculations. As surface free energy can give you more information on your surface compared to the contact angle measurements alone, it is time well spent to study the different theories more in detailed.
Calculate critical surface tension or surface free energy for a solid by testing against a series of liquids and measuring the contact angles.