Selective Surface Modification of a Fluorocarbon Resin Into Hydrophilic Material Using an Excimer Laser
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SELECTIVE SURFACE MODIFICATION OF A FLUOROCARBON RESIN INTO HYDROPHILIC MATERIAL USING AN EXCIMER LASER M. OKOSHI, Graduate Student of Faculty of Eng., Tokai University M. MURAHARA, Faculty of Engineering, Tokai University, 1117 Kitakaname, Hiratsuka, Kanagawa 259-12, JAPAN K. TOYODA, Riken, The Institute of Physical and Chemical Research, 2-1 Hirosawa, Wako, Saitama 351-01, JAPAN ABSTRACT Selective surface modification of fluorocarbon resin has been demonstrated by using an ArF excimer laser beam and an ammonia The fluorocarbon complex which was made from NH3 and B2H6 gases. NH3 molecules which resin was set in the atmosphere of NH3 gas. with the B2H6 on the surface reacted quickly were adsorbed As a result, the molecules, and an ammonia complex was produced. The resin surface was complex was adsorbed on the surface. The complex and C-F bonds selectively irradiated by ArF laser beam. of this resin were excited by the laser beam, and the surface was The modified selectively modified to be hydrophilic property. samples were evaluated by XPS analysis, measuring the contact angles of the water and the SEM image on the surface. Introduction Studies on biomaterials have done extensively in recent years. Among these materials, fluorocarbon resin (Teflon) has a smooth its harmony and an optimum life for surroundings because of corrosion and durability resistance. Also, it has low-friction and as physical properties. Moreover, the interatomic insulation distance of C-F bond structuring this resin is very close to that of Therefore, it is a human-friendly material inside the the C-H bond. body. It is well known that an artificial blood vessel requires hydrophilic parts on the inner wall of the teflon tube in order to obtain an anti-clotting property. Surface modifications of the fluorocarbon resin are usually carried out by chemical treatment using alkaline-metal solution and the physical method in which However, these material surface is irradiated by the rf plasma. methods cannot avoid damages to the surface of the basic material The authors and have difficulties in selective modification. proposed the modification technique for the fluorocarbon resin surface to turn to oleophilic material using an excimer laser [1]. In this paper, we report on the selective photomodification of the resin into hydrophilic material for the purpose of medical use. Photochemical Reactions following two The photochemical reaction must satisfy conditions: first, absorption of a material must agree with the wavelength of the laser, and second, the laser's photon energy must be higher than the dissociation energy of the atoms or molecules of the material. The UV spectra of the fluorocarbon resin and the reaction gases of the both NH3 and B2H6 are shown in Fig. 1 and Fig. 2. These figures indicates that both the resin and the gases has the absorption band at the 193nm wavelength of the ArF excimer laser. Furthermore, the ArF laser's photon energy (147kcal) is energy (128kcal). Therefore, the higher than a C-F binding photochemical reaction is car
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