Micelle growth of cationic gemini surfactants studied by NMR and by time-resolved fluorescence quenching

Ali Reza Tehrani-Bagha; Krister Holmberg; Magnus Nydén; Lars Nordstierna

doi:10.1016/j.jcis.2013.04.050

Micelle growth of cationic gemini surfactants studied by NMR and by time-resolved fluorescence quenching

J Colloid Interface Sci. 2013 Sep 1:405:145-9. doi: 10.1016/j.jcis.2013.04.050. Epub 2013 May 21.

Authors

Ali Reza Tehrani-Bagha¹, Krister Holmberg, Magnus Nydén, Lars Nordstierna

Affiliation

¹ Department of Chemical and Biological Engineering, Chalmers University of Technology, SE-412 96 Göteborg, Sweden.

PMID: 23746684
DOI: 10.1016/j.jcis.2013.04.050

Abstract

The micelle growth of a series of five cationic gemini surfactants has been investigated by time-resolved fluorescence quenching (TRFQ) and by two NMR techniques, line width analysis and diffusometry. The surfactant series was designed such that the effect of a number of variables could be assessed: length of the spacer unit, presence of ester bonds in the tails close to the head groups, and presence of a hydroxyl group in the spacer. For the gemini with long spacer, the micelles remained relatively small in size upon an increase of the concentration. The gemini surfactants with short spacer, on the other hand, showed a considerable micellar growth as the concentration was raised. It is of particular interest that the relatively simple line width analysis of one dimensional (1)H NMR spectra gave qualitatively the same results as the more sophisticated TRFQ and NMR diffusometry techniques.