Studies on low-temperature bonding mechanism of VUV and plasma pretreated cyclo-olefin polymer

To investigate the mechanism underlying the low-temperature direct bonding of cyclo-olefin polymer (COP), ATR-FT-IR and XPS surface analysis methods and contact angle measurements were carried out for COP samples. Oxygen plasma, vacuum-ultraviolet (VUV), and VUV/O₃ were selected for pretreatment. Surface analyses results showed that polar functional groups (e.g., -OH, -COOH) are generated by each treatment. These groups are expected to generate hydrogen bonds on the surfaces of the pretreated COPs at room temperature. After annealing, some hydrogen bonds are expected to change to -C-O-C-. This bond becomes strong after pretreatment followed by low-temperature bonding.