LAUSR

Wetting behavior of aqueous solutions of four polyoxyalkylated diethylenetriamine (DETA) polymeric surfactants (named A–D) are studied and pH effect is assessed. Surfactants A, B and C have a ‘star-like’ structure differing only by the number of polymeric branches: 4, 6 and 9 in the mentioned order while the forth one, D, is of a dendritic type with 4–6 primary and 2–3 secondary branches. Experimental data about liquid/air surface tension, contact angle θ and equilibrium wetting film thickness of the surfactant solutions in pH range of 1–12 are obtained. The liquid/solid and the air/solid surface tension are calculated using the empirical equation of state and Berthelot’s combining rule. Results from the studies indicate that pH affects polymer solution properties at liquid/solid and liquid/air interfaces, and influences parameters such as surface tension, solid surface hydrophobicity, equilibrium film thickness, etc.