PET has been widely used for medical materials such as an artificial ligament. However, the affinity of tissues is no good. To compensate this, the mesh formed PET has clinically been used for artificial ligament intruding tissue into mesh. However, this method has not shown sufficient affinity with the tissue; that is, the initial adapting strength of the material and tissue is weak. · The artificial ligament must be biocompatible to contact blood and tissue. The foregoing artificial ligament, however, doesn't satisfy the biocompatibility. ·
Thus, we have modified the PET surface into hydrophilic by substituting NH2 or OH functional groups. Firstly, an ArF excimer laser light was irradiated the PET with water on top. The OH functional group was substituted on the PET surface by this photochemical reaction. Secondly, the ArF excimer laser light was irradiated the PET in ammonia gas ambient. In this photochemical reaction, the NH2 functional group was substituted on the PET surface.
· In this study, the untreated sample had the contact angle with water of 80 degrees and the bonding strength with protein of only 1.0kg/cm2. The contact angle of the modified sample improved to 40 degrees and the bonding strength, to 23kg/cm2. When treated in ammonia gas, the contact angle also improved to 40 degrees; however, the bonding strength was almost the same as that of the untreated sample.
It was confirmed that the affinity of the PET for water and protein could be controlled by increasing or decreasing the substitution concentration of OH and NH2 functional groups on the surface.