Low-cost plasma treatment
Oxygen plasma cleaners are a very commonly used tool when bonding PDMS sheets to materials such as PDMS, glass, Si, and SiN. Even though plasma cleaners have proven to be highly effective and reliable tools in this application, they continue to be relatively costly pieces of laboratory equipment. It has been realized that corona discharge wands can serve as a more affordable, yet still effective, alternative.
Figure 1: Hand-held corona treatment wand.
Corona discharge treatment is commonly used as a contact-angle modification method in large scale thin film production. Although contact-angle modification is not the application in this instance, successful surface treatment that will lead to a secure bond does inherently alter contact angle (Figure 2).
Figure 2: Water droplet on glass A. Prior too treatment B. immediately after treatment.
Figure 3: Energized wand tip.
Successful bond procedure entails 60 seconds of treatment with the wand on both surfaces to make contact. The surfaces are then brought into contact and placed in an oven for 5 minutes at 100C to more rapidly “cure” the bond. Note: the corona discharge rapidly generates high concentrations of ozone, it is strongly advised to conduct all treatment in a fume hood to avoid exposure.