A study of the thermodynamic properties of surfactant mixtures: Mixed micelle formation and mixed surfactant adsorption
The volumetric mixing in anionic/nonionic, cationic/nonionic, and anionic/cationic mixed micelles was determined by examining the total surfactant apparent molar volumes at total surfactant concentrations much greater than the mixture critical micelle concentration. The mixed surfactant systems investigated were: sodium dodecyl sulfate and a polyethoxylated nonylphenol, at 0.15 M NaCl and with no added NaCl; cetyl pyridinium chloride and polyethoxylated nonylphenol, at 0.03 M NaCl; and sodium dodecyl sulfate and dodecyl pyridinium chloride, at 0.15 M NaCl. The results of this study suggest that the electrostatic interactions in the mixed micelles do no significantly effect the molar volume of the mixed micelle. Therefore, the micelle hydrophobic core dominates the volumetric mixing in mixed micelles. The adsorption of sodium dodecyl sulfate and a polyethoxylated nonylphenol and well defined mixtures thereof was measured on gamma alumina. A pseudo-phase separation model to describe mixed anionic/nonionic admicelle (adsorbed surfactant aggregate) formation was developed. In this model, regular solution theory was used to describe the anionic/nonionic surfactant interactions in the mixed admicelle and a patch-wise adsorption model was used to describe surfactant adsorption on a heterogeneous surface. Regular solution theory was tested on specific homogeneous surface patches by examining constant total surfactant adsorption levels. For the adsorption of binary surfactant mixtures adsorbing at total equilibrium concentrations above the mixture critical micelle concentration, simultaneous solution of the pseudo-phase separation models for mixed admicelle and mixed micelle formation predicts that the surfactant compositions in the monomer, micelle, and admicelle pseudo-phases are constant at a constant total adsorption level.
- Research Organization:
- Oklahoma Univ., Norman, OK (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States); National Science Foundation, Washington, DC (United States); Environmental Protection Agency, Washington, DC (United States); Department of the Interior, Washington, DC (United States)
- DOE Contract Number:
- FG05-87ER13678; FG22-87FE61146
- OSTI ID:
- 10146356
- Report Number(s):
- DOE/ER/13678-75; ON: DE94010827; BR: KC0302020; AA0510000/AA1505000; CNN: Grant CBT-8814147; Grant G1125132-4001; Grant R-817450-01-0; TRN: AHC29410%%9
- Resource Relation:
- Other Information: TH: Thesis (Ph.D.); PBD: 1992
- Country of Publication:
- United States
- Language:
- English
Similar Records
Surfactant loss control in chemical flooding: Spectroscopic and calorimetric study of adsorption and precipitation on reservoir minerals. Quarterly technical progress report, April 1, 1993--June 30, 1993
The use of micellar solutions for novel separation techniques