Abstract
In order to investigate the wetting properties of polymer films in aqueous phase, critical interfacial tensions were estimated by measuring advancing contact angles of droplets of several oils on polymer films in water. The critical interfacial tensions of polymer films were as follows; polyamide 4, polyester 12, polypropylene 22, polytetrafluoroethylene 29 dyne/cm. This is reverse to the order of the critical surface tensions obtained from droplets of aqueous sodium dodecyl sulfate in air. It was found that the higher the surface energy in air, the lower the surface energy in water.
Another series of experiments for the wetting of n-hexadecane, was carried out in aqueous solution of surfactans. The contact angle of this oil drop against polymer film increased remarkably to exceed the critical micelle concentration of surfactants and it was found that cos θ increased with increasing interfacial tension. This tendency is just reverse to that obtained in absence of surfactant.
