The relationship between the adhesion work, the wettability and composition of the surface layer in the systems polymer/aqueous solution of anionic surfactants and alcohol mixtures

Abstract

Measurements of advancing contact angle ( θ) were carried out on polytetrafluoroethylene (PTFE) and polymethylmethacrylate (PMMA) for aqueous solution of sodium dodecyl sulfate (SDDS) mixtures with methanol, ethanol and propanol in the range of SDDS concentration from 10 −5 to 10 −2 M, and for sodium hexadecyl sulfonate (SHS) with the same alcohols at the SHS concentration ranging from 10 −5 to 8 × 10 −4 M at 293 K. The concentration of methanol, ethanol and propanol used for measurements varied from 0 to 21.1, 11.97 and 6.67 M, respectively. On the basis of the contact angles the critical surface tension of PTFE and PMMA wetting was determined by using for this purpose the relationship between the adhesion and the surface tension and cos θ and surface tension both at constant alcohol and surfactant concentration, respectively. The obtained contact angles were also used in the Young Dupre’ equation for calculations of the adhesion work of aqueous solution of mixtures of anionic surfactants and short chain alcohols to PTFE and PMMA surface. The adhesion work calculated in this way was compared to that of the particular components of aqueous solution to these surfaces determined on the basis of the surface tension components and parameters of the surface tension of the surface active agents, water, PTFE and PMMA from van Oss et al. equation. The calculated adhesion work was discussed in the light of the concentration of surface active agents at polymer–water and water–air interface determined from Lucassen-Reynders, Gibbs and Guggenheim-Adam equations.