AGING EFFECTS ON POLYETHYLENE FILM SPUTTERED BY USING RADIOFREQUENCY

Aging effects on a polyethylene film deposited by radio-frequency sput tering on a quartz crystal microbalance was examined by measuring reso nance frequency and conductance. The film was also analyzed by infrare d and electron spin resonance spectroscopies. With increasing the time for exposing to air, the film weight increased and its viscosity decr eased. Oxygen was observed in the fabricated film, and the amount incr eased with exposure to room air while the spin concentration decreased . These results indicated the softening of the film and the reconstruc tion of the film structure: the enrichment of the oxygenated moieties on the film surface due to the reactions between radical sites in the film and reactive species in the air, such as oxygen and water, and to movement of hydrophilic moieties inside the film towards the surface. When stored in vacuum, the film hardened and oxidation slowered. This is probably due to the reaction of the active sites in the film with hydrocarbons in the air, to the reactions among the active sites in th e film, and to movement of hydrophilic moieties from the surface to in side the film.