Surface characteristics of UV-irradiated collagen/PVP blended films

The surface properties of collagen/poly(vinyl pyrrolidone) (PVP) blended films before and after UV-irradiation lambda = 254 nm) were investigated using the technique of atomic force microscopy (AFM) and by means of contact angle measurements allowing the calculation of surface free energy. Measurements of the contact angle for diiodomethane (D), formamide (F) and glycerol (G) on the surface of collagen, PVP and collagen/PVP films were made. It was found that collagen/PVP blend surface is enriched in low surface energy component i.e. collagen. The contact angle and the surface free energy were altered by UV-irradiation for both collagen and PVP films, however, the changes of these parameters were much smaller for the film of collagen/PVP blend. It was concluded that the studied blend is more photo-resistant than the pure components. The AFM images have shown that collagen surface morphology is somehow ordered in contrary to that of PVP. The blend surface was similar to that of pure collagen. UV-irradiation caused only rather small changes in the surface morphology of all studied films. (C) 2004 Published by Elsevier B.V.