Chemical and morphological modification of polyethersulfone membrane and film following krypton florid laser irradiation

Formation of laser-induced surface micro/nanostructures and chemical modification on the surface of polyethersulfone (PES) film and composite membrane were studied. Laser irradiation was carried out by ultraviolet (248 nm) laser pulses at a fluence below the ablation threshold. The motivation was to investigate the effect of the structure (film and asymmetric/symmetric membrane), as well as addition of polyvinylpyrrolidone, on morphological and chemical changes after laser irradiation. Nano grains were formed on the surface of the membrane, where the difference in density was observed due to the different membrane structures and composition; while nano ripples were formed on the surface of the PES film. To monitor the modification of chemical properties of the surface after irradiation, attenuated total reflectance Fourier transform spectroscopy as well as contact angle measurement were performed. Finally, the physicochemical modifications caused by irradiation were discussed.