Role of Counterion in the Adsorption of Ionic Amphiphiles at Fluid Interfaces
2024

Role of Counterion in the Adsorption of Ionic Amphiphiles

publication Evidence: high

Author Information

Author(s): Lunkenheimer Klaus, Geggel Katrina, Hirte Rolf, Seibt Horst, Kriwanek Joerg

Primary Institution: Max-Planck-Institut für Kolloid und Grenzflächenforschung

Hypothesis

The surface excess of the adsorbed anionic surfactant is exclusively determined by the cross-sectional area of the positive counterion.

Conclusion

The study confirms that negatively charged counterions interact more strongly with water than positively charged ones.

Supporting Evidence

  • The study extends a new model of adsorption to negatively charged counterions.
  • Hydration behavior differs significantly between positively and negatively charged ions.
  • Negatively charged halide ions have a greater hydration layer than positively charged alkali ions.

Takeaway

This study shows that the size of the counterion affects how well surfactants stick to surfaces, and negatively charged ions stick better than positively charged ones.

Methodology

Surface tension measurements were conducted using a LAUDA ring tensiometer to evaluate the adsorption properties of cationic surfactants.

Potential Biases

Potential biases may arise from the quality of the surfactants and the experimental methods used.

Limitations

The purity of the surfactants used was a significant concern, affecting the accuracy of the results.

Digital Object Identifier (DOI)

10.1021/acs.langmuir.4c01259

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