Study of the effects of incorporation of UV-absorbing compound in parylene C films

Novel thin films of UV-absorber-doped parylene C were produced by a deposition technique consisting in a coarse vacuum co-evaporation of parylene C dimer and 2-hydroxy-4-(octyloxy)benzophenone (UVabs). Co-deposited samples were obtained by evaporating UVabs compound at temperatures ranging from 100 °C to 120 °C. The films were characterized by Fourier transform infrared (FT-IR) analysis, Rutherford backscattering spectrometry (RBS), x-ray diffraction (XRD), atomic force microscopy (AFM), optical absorption and emission spectroscopy. RBS and XRD analyses show that the UVabs evaporation strongly affects the deposition and growth of parylene film, giving rise to a significant increase in the film thickness and to a change in the microstructure. UV photodegradation tests of the co-deposited samples were carried out in air and showed that the photodegradation of co-deposited samples was slower than that of parylene alone, but the change in the film microstructure as induced by absorber incorporation gave rise to a faster deterioration of the C-Cl groups.