ABSTRACT The determination of the surface tension of some liquids or solutions has been carried out using a tensiometer. The determination of the contact angle between the liquids and a planar surface has also been carried out using photography. Polar and dispersive contributions of the surface tension were obtained by calculation while the polarities of the liquids and solutions were determined applying Wu equations. This method gave the different results for solutions prepared from macromolecular compounds (acroleine -ethanolamine macromolecular solution 1g/l, acroleinediethanolamine macromolecular solution 1g/l, polyglutaraldehyde-ethanolamine macromolecular solution 0.7 g/l and polyglutaraldehyde -diethanolamine macromolecular solution 1 g/l) synthesized by Malonda from glutaraldehyde and acroleine. The dispersive and polar contributions of the surface tension were computed and used to calculate the interfacial tensions of solutions by the simple measurement of the contact angle. The results have revealed that the computed interfacial tensions were comparable to the values measured directly by the tensiometer for polyglutaraldehydeethanolamine macromolecular solution 0.7 g/l and polyglutaraldehyde -diethanolamine macromolecular solution 1 g/l) making an interface with Soltrol-130 of 17.1 and 16.9 dynes/cm compared to direct measured values of 17.2 and 17.7 dynes/cm respectively representing 1% and 5% error, respectively
