Journal of Surfactants and Detergents

, Volume 5, Issue 2, pp 151–157

The role of hydrophilic linkers

  • Edgar Acosta
  • Hirotaka Uchiyama
  • David A. Sabatini
  • Jeffrey H. Harwell


In microemulsion formulations, linker molecules are additives that can enhance the surfactant-oil interaction (lipophilic linkers) or the surfactant-water interaction (hydrophilic linkers). In this paper, the role of the hydrophilic linker is elucidated through solubilization studies, interfacial tension studies, and by studying the partitioning of the hydrophilic linker into an optimum middle phase. This research used alkyl naphthalene sulfonates as the hydrophilic linkers, sodium dihexyl sulfosuccinate as the surfactant, and trichloroethylene as the oil phase. The hydrophilic linkers were found to have interfacial properties between a hydrotrope and a cosurfactant. More specifically, the data show that a hydrophilic linker is an amphiphile that coadsorbs with the surfactant at the oil/water interface but that has negligible interaction with the oil phase. The role of the hydrophilic linker can thus be interpreted as opening “holes” in the interface. Based on the characteristics of alkyl naphthalene linkers, carboxylic molecules were evaluated as hydrophilic linkers. For trichloroethylene microemulsions, sodium octanoate was found to be an alternative hydrophilic linker to sodium mono- and dimethyl naphthalene sulfonates.

Key Words

Hydrophilic hydrotrope linker microemulsion octanoate trichloroethylene 


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Copyright information

© AOCS Press 2002

Authors and Affiliations

  • Edgar Acosta
    • 1
  • Hirotaka Uchiyama
    • 1
  • David A. Sabatini
    • 2
  • Jeffrey H. Harwell
    • 1
    • 3
  1. 1.Chemical Engineering and Materials Science DepartmentNorman
  2. 2.Civil Engineering and Environmental Science DepartmentNorman
  3. 3.College of EngineeringNorman
  4. 4.School of Civil Engineering and Environmental ScienceThe University of OklalhomaNorman

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