Determination of spreading pressure and its effect on polymer surface tension from contact angle data. Combination of the two-liquid contact angle method with the one-liquid contact angle method

Abstract —A novel analysis to determine the spreading pressure, πw, for water-polymer interactions from contact angle data is proposed by using Good's interaction parameter (Φ) formalism. In this method, first measurement of the contact angles of water drops on the polymer in different hydrocarbons in the two-liquid method is performed; then the contact angle determination of a water drop on the same polymer sample in the one-liquid method is carried out. The data obtained from the one-liquid method are evaluated by using the data obtained from the two-liquid method in order to calculate πw. This method does not require the use of Φ values calculated in terms of statistical mechanics, due to the fact that the product Φ γs.1/2 can be readily calculated from experimental data. The precise contact angle data reported by Tamai et al. (J. Colloid Interface Sci. 60, 112 (1977)) are used in the calculations and good agreement is obtained with the πw data obtained from independent adsorption measurements. Keywords: Polymersurface tensionspreading pressurecontact anglecombined one-two-liquid methods