Clouding and Hydrodynamic Behavior of Pluronic-Surfactant Interaction in Aqueous Salt Solutions

Abstract

Clouding behavior of PEO-PPO-PEO and PPO-PEO-PPO block copolymers were studied in presence of sodium dodecyl sulfate (SDS) and NaCl. Extensive study of Pluronic P84 (EO₁₉PO₄₃EO₁₉) with different salts and ionic surfactants, were carried out using cloud point, viscosity and dynamic light scattering (DLS) measurements. The change in cloud point, as well as the size of P84 micelles in aqueous salt solution obeys the Hofmeister lyotropic series. Results on P84-ionic surfactant mixture indicate stronger interaction in case of SDS compared to those in presence of dodecyl trimethylammonium chloride (DTAC); here interaction seems to diminish in the presence of salts.

Keywords:

• Cloud points
• dynamic light scattering
• interaction
• Pluronics
• surfactants

The author gratefully acknowledges Dr. P. A. Haasan (Chemistry Division, BARC, Mumbai, India) for providing facilities for dynamic light scattering (DLS) measurements.

Notes

^a Data were taken BASF product specifications.

^b Experimental data.

^c Hydrophilic–lipophilic balance; the HLB values for the copolymers were taken from BASF product specifications.