How Can Plasma Activation be Measured?

Contact angle, Test Inks or Cross-cut tests

Contact angle

The  contact angle  is the angle that is formed when observing the projection of the drop lying on the  solid  by the tangent to the drop contour with the surface of the solid in the  three-phase point  . According to the physical definition, a  surface  with a contact angle  smaller than 90 ° is hydrophilic  (wettable), and larger than 90 ° hydrophobic  (non-wettable). The contact angle can be  changed  (increased or decreased) by means of  plasma treatment . A suitable plasma process or application of a suitable coating in a plasma process enables hydrophilic  in Convert hydrophobic  surfaces ( vice versa through hydrophilic layers  ). 

Test inks

Measuring device for estimating the  surface energy : If the test ink contracts after application to the surface, the  surface energy of  the solid is  lower  than that of the ink, if the  wetting is retained , the  surface energy of  the solid is  equal to  or  greater  than that of the liquid. By using series of test inks with  graduated  surface energy, the  total surface tension of  a solid can be determined. The  polar  and  non-polar The proportion of surface energy can not be  determined with this method  .

Cross-cut test 

The  adhesion  of coatings  to check, one is  cross-cut test (standards: DIN EN ISO 2409 and ASTM D3369-02) performed. After painting, the lacquer layer of the plastic part is   cut into a grid . Then a  standardized  adhesive tape is  glued to the  cutting grid,  pressed on  and  pulled off again with a  jerk . Will  paint  the tape  hanging , the adhesion of the coating is  defective . The cross-cut shows the  adhesive strength of layers of paint on plastic parts.

To learn more about the use of plasma in manufacturing, please read our eBook titled "Manufacturer’s Surface Activation Guide for Improved Adhesion."