Solving an Adhesion Failure for a Medical Device

Through Battelle’s Surface Science program we identified an atmospheric plasma treatment as an approach to solve the adhesion problem and avoid changes to the product design or manufacturing process. Battelle’s Surface Science program is focused on development of smart, functional surfaces and coatings tailored to specific client needs. Battelle applies cutting-edge discoveries in material sciences to develop practical, scalable solutions for real-world product problems. For the medical device manufacturer, we first needed to better understand the actual conditions under which the product was being used and the conditions that led to failure of the adhesive. Battelle researchers looked at how the customer uses the product and how variables such as heat, humidity, cycling load and user behaviors interact. Our analysis showed that the initial product validation studies did not fully account for the interaction between all of the variables. We developed a new validation process in order to test alternatives for improving the adhesion between the glass and plastic components.

Adhesion is influenced by two properties: the topography and microstructure of the surfaces to be joined, and the chemical interactions between the surfaces and the adhesive used to join them. We needed to find a way to change one of these variables in order to improve adhesion without requiring substantial changes to the product design, component materials or manufacturing process. Our solution used an atmospheric plasma treatment to change the surface topography and surface energy of the limiting interface, the PEEK, resulting in better physical wetting between the two parts. Atmospheric plasma treatment, in which surfaces are exposed to a partially ionized gas, or plasma jet, changes the microstructure and surface energy of the treated material. Plasma treatment of the PEEK created a structure that allowed for better surface-to-surface contact between the parts and better bonding with the adhesive.