Optimization of dielectric barrier discharge reactors for high-speed surface treatment of polymer substrate

Summary form only given. Poor adhesive property of polymers limits their application to the flexible substrate. Low-temperature plasmas, produced by the dielectric barrier discharge (DBD) reactor, are known to be highly effective for the improvement in polymers´ adhesion. In this work, we tried to find the optimum DBD structure for surface treatment of a polymer substrate. Four kinds of DBD reactor, characterized by L-shaped electrode structure and bipolar voltage pulse driving, are designed and fabricated. Their discharge characteristics are compared by taking the time-averaged images and spatial-temporal evolutions of the discharge. By varying the moving speed of a polyimide (PI) film, the water contact angles are measured for different applied voltages. The changes in surface property of the PI film before and after plasma treatment are evaluated by using the X-ray photoelectron spectroscopy (XPS) and atomic force microscope (AFM). Finally, the optimum reactor structure for high-speed surface treatment of polymer substrates is determined based on the experimental results.