The wettability of polytetrafluoroethylene and polymethylmethacrylate with regard to interface behaviour of Triton X-165 and short chain alcohol mixtures:: II. Adsorption at water–air and polymer–water interfaces

On the basis of the contact angle data presented in the previous paper, the surface concentration of alcohols and TX-165 at PTFE–water and PMMA–water interfaces was determined. For this determination the polymer–solution interface tension was calculated from the Young equation by using the literature data of the polymers surface tension. Taking into account the Gibbs and Guggenheim-Adam adsorption isotherms of Triton X-165 and alcohols their molar fractions and activity coefficients were determined. Next, the free enthalpy of Triton X-165 and alcohols mixing in the adsorption monolayer at polymer–solution interface was calculated. From the theoretical analysis of the adsorption of the Triton X-165 and alcohols it results that the total adsorption of the mixture and its individual components at PTFE–solution and solution–air interface is nearly the same, but the total adsorption at PMMA–solution interface is considerably lower than that at solution–air one, and the composition of the mixtures at both interfaces is different. It can be also stated that the activity coefficients of Triton X-165 and alcohols in the surface region at solution–air and polymer–solution interface are different.