Dispersion and Polar Force Components of Surface Tension of Some Polymer Films

The surface tension and the dispersion and polar components of the surface tension for solids and liquids were estimated by contact angle measurement in order to apply these concepts to a detergency study. Two approximation methods, the extended Fowkes' equation and Wu's equation, were adopted for the calculations. Among the twelve experimental liquid pairs, methylene iodide/water and tricresyl phosphate/water gave values for paraffin, polyethylene, and polystyrene close to the average for the twelve pairs. Values for cellulost acetate and cellophane were there fore obtained using these two pairs. The results showed that the dispersion force component becomes larger with increasing degree of acetylation, while the polar force component becomes smaller.