How to measure the effect of treatment

1. Use of test reagents (Plastics－Film and sheeting－Determination of wetting tension (JIS K6768))

Apply a reagent on the surface of the specimen and wait for two seconds. See whether or not the liquid film breaks after two seconds. The value of a mixture that keeps the surface wet for exactly seconds is the surface tension of the base material.

Not wet
Check it again with a reagent with a lower value.

Wet
The value of this reagent is regarded as the wetting tension index.

An example of data on watt density and wetting tension (PET - Outline)

2. Contact angle method

Apply an arbitrary liquid on the surface of the solid specimen to be tested and measure the angle of the wetted surface, which will be the contact angle. The contact angle is widely applied as a criterion for judging the wettability of materials and liquids. Many users also apply it for testing wettability on the corona surface treatment as an approach different from the use of test reagents.