Three-phase behavior of surfactant-polymer mixture
Advancing the chemical engineering fundamentals
Interfacial & Colloidal Phenomena - I (T2-6a)
Keywords: surfactant, cloud point, micellar solution, associative polymer, phase separation
Phase separation of nonionic surfactant in the presence of associative polymer was studied experimentally. The specific system is a Triton X-114 or Triton X-100 solution with addition of hydrophobically modified hydroxyethyl cellulose (HMHEC). When the temperature was higher than the cloud point, the solution could separate into three macroscopic phases if the surfactant concentration falls within a certain range: a cloudy phase in between two transparent phases. The formation of three phases could be observed a few hours after the solution turned cloudy, depending on the solution composition. The three phases could persist as long as a month with volumes being nearly unchanged. It is interesting to find that the volume of the middle cloudy phase shows a certain correlation with the global polymer concentration, implying that most of polymer stays in this phase. This finding is verified by composition analysis using UV to meaure both the surfactant and polymer concentrations in each of the three phases. We also found that the bottom phase is a surfactant rich micellar solution, while the top phase is both surfactant and polymer lean.
Presented Wednesday 19, 15:00 to 15:20, in session Interfacial & Colloidal Phenomena - I (T2-6a).
