Topic: Test ink: measurement method to determine surface tension - determining surface tension, define surface tension, good wetting of the surface

Test ink: Test method for determining surface tension using Plasmatreat test ink

Surface tension decreases in the course of storage

As in every test method, in determining surface tensions by means of test inks critical examination of the test results is necessary. The surface tension determined can always be only a measure of the instantaneous state of the substrate, because as is well known surface tension decreases as the duration of storage increases.

How do test inks react?

If the liquid wets the surface after application the surface tension of the material being tested is higher than the corresponding test value. The test is repeated with the next higher test value until wetting fails to occur. Accordingly, the surface tension of the material corresponds to the value of the test ink that last wetted it for at least 2 seconds.

Evaluation of the test results obtained with the Plasmatreat test ink:

Poor wetting of the surface	Good wetting of the surface