SURFACE PROPERTIES OF CHITOSAN ACETATE, POLYACRYLAMIDE AND THEIR MIXTURES

The surface properties of chitosan acetate (ChA), polyacrylamide (PAM) and ChA/PAM mixtures have been investigated by the tapping-mode atomic force microscopy (AFM) and monitored by contact angle measurements. Chitosan is blended with polyacrylamide in acetic acid solution and this solution is cast to prepare the mixture film. Measurements of the contact angle for two different liquids (diiodomethane and glycerol) on the surface of chitosan acetate. The surface free energy (gamma(p)(s)) as well as dispersive (gsd) and polar (gsp) components were calculated from contact angle values by Owens-Wendt methods using an appropriate computer program. The values of polar and dispersive components of surface free energy show that PAM films are more polar than chitosan acetate films. In the case of ChA/PAM mixtures, the values of surface free energy and polar component are reduced significantly compared with pure polymers. This behavior indicates rather hydrophobic character of this surface. The changes of topography images were considered by determining the root mean square (RMS) deviation in the image data. The study of blends by AFM showed a completely different morphology when compared with pure components. The roughness of blends increases with the increase of ChA content. This may indicates a strong interaction between the polymeric components.