Influence of UV irradiation in nitrogen and air environment on dielectric properties of ultrathin polysulfone films revealed using surface plasmon resonance method

The behavior of the dielectric constant of polysulfone is investigated under various regimes of UV irradiation with wavelengths of 254 and 366 nm using in situ surface plasmon resonance method. The measurements were accomplished in air and nitrogen environments. In the nitrogen atmosphere, it was revealed the unexpected and essential increase in the dielectric permittivity of polysulfone under UV of a wavelength of 254 nm, which was ascribed to photolysis of bonds in the polymer chain followed by crosslinking. The details of kinetics of the dielectric constant under UV irradiation are discussed.