Atmospheric pressure plasma press for improved adhesion between flexible polymer(Prepreg) and inorganic material(BaTiO3)

For the strongest bonding between two different materials, a novel adhesion process called “plasma press” has been studied using an atmospheric pressure plasma and the effect of plasma press between a flexible substrate (adhesive polymer substrate; Prepreg) and an inorganic material (BaTiO3) has been investigated as an application to the multilayer flexible printed circuit board for next generation flexible mobile electronics and wearable electronics, where, the adhesion between the flexible polymer substrate and an inorganic material is very important. Plasma press is a process of hot pressing two different surfaces for adhesion while operating a plasma between the surfaces for the activation of the surfaces. Compared to conventional hot pressed sample, the plasma pressed sample showed about 130 % increase in the adhesion strength between the Prepreg and BaTiO3. The surfaces inspected after the adhesion test showed that the fracture surface is BaTiO3 material itself not the interface between the BaTiO3 and Prepreg for the plasma press indicating a much stronger bonding at the interface than the BaTiO3 material itself. The stronger bond for the plasma pressed sample is believed to be related to the formation of active carboxyl functional groups such as CO, OCO, OCOO, etc. and unsaturated dangling bonds on the materials surfaces by the plasma operating during the hot press for bonding.