The influence of UV irradiation on the surface of chitosan films

The surface properties of chitosan films before and after UV-irradiation (λ = 254 nm and 248 nm, respectively) were investigated using the technique of scanning electron microscopy (SEM) and by means of contact angle measurements allowing the calculation of surface free energy. Moreover, in order to determine the film mass changes, quartz crystal microbalance (QCM) measurements were performed. Measurements of the contact angle for diiodomethane (D), formamide (F) and glycerol (G) on the surface of chitosan films were made. The chemical and structural changes during UV irradiation were studied by FTIR-ATR spectroscopy.The contact angle and the surface free energy were altered by UV irradiation of chitosan films. The microscopy images have shown that the KrF excimer laser irradiation caused visible damages on the surface in comparison with the surface exposed to the mercury UV lamp. The surface modification of chitosan films can be achieved using both, the low intensity UV lamp and the excimer laser.