Effect of water-soluble polymers on the surface properties of 3-(dimethyldodecylammonio)propanesulfonate in aqueous solutions

Using surface tension measurements the interaction between 3-(dimethyldodec ylammonio)propanesulfonate, DPS, and poly(vinylpyrrolidone), PVP, poly(acry lic acid sodium salt), PAC, and poly(sodium 4-styrenesulfonate) PSS, has be en studied. No interaction between PVP and PAC and the surfactant was obser ved, while a significant interaction with PSS was detected. The dependence of the equilibrium surface tension on the surfactant concentration is inter preted by means of the phase transition model (Langmuir 1991, 7, 1055). Dyn amic surface tension of DPS solutions in the absence and presence of polyme rs was determined by using the drop-volume tensiometer. The surfactant adso rption kinetics on the interface is a diffusion-controlled process. Two asy mptotic solutions, at-long times and at short times, to the classic Ward an d Tordai equation were used to fit dynamic results. At long times there is evidence of the intermolecular attractions between the surfactant molecules at the interface in good agreement with the equilibrium surface tension re sults.