Direct bonding of PFTF sheets assisted by shynchrotron radiation induced surface modification

Abstract

Characteristics of the microfabrication and modification of polytetrafluoroethylene (PTFE) using X-ray photo decomposition desorption and ablation are studied in the highest energy region (2 keV to over 12 keV). We have discussed that the PTFE polymer takes liquid state due to irradiation of high-energy photons with high-penetration depth, and this leads to the dominant decomposition, photo-induced ablation of PTFE and following generation of the volatile fragments including PTFE polymer itself. Furthermore, we found that melting point of the surface bulk layer of PTFE drastically decreased due to the irradiation of SR. The result of the differential thermal analysis of the SR-irradiated PTFE sheet shows the decay of the weight of PTFE sheet induced by thermal desorption starts at 155°C. This suggests that the apparent melting point of PTFE of which surface is modified by SR irradiation decreases drastically from original melting point. We finally successfully demonstrated that the two PTFE sheets could be bonded directly at low temperature less than 200°C without bonding reagent.