Comparison of oleyl and elaidyl isomer surfactant-counterion systems in drag reduction, rheological properties and nanostructure.
Compared with quaternary ammonium cationic surfactants with saturated alkyl chains, quaternary ammonium cationic surfactants with one double-bond in their alkyl chains, when mixed with appropriate counterions (in certain molar concentration ratios, ξ), can reach much lower effective drag-reduction temperatures, while maintaining the upper drag-reduction temperature limit of the corresponding saturated drag reducing surfactant solutions. No previous study has compared the effects of cis- vs. trans-unsaturated alkyl hydrocarbon tail configurations (oleyl vs. elaidyl) trimethyl ammonium chloride cationic surfactants at different counterion/surfactant concentration ratios on micellar nanostructures, (1)H NMR spectra and on rheological and drag-reduction behavior of their solutions. Since neither pure oleyl (cis-) nor elaidyl (trans-) trimethyl ammonium chloride surfactants are commercially available, they were synthesized and their 5mM solutions with NaSal counterion at concentrations of 5mM, 7.5mM and 12.5mM were studied.
Department of Chemical and Biomolecular Engineering, The Ohio State University, Columbus, OH 43210, USA. yunying.qi@gmail.com
Yunying
Y
Qi
Ellina
E
Kesselman
David J
DJ
Hart
Yeshayahu
Y
Talmon
Anthony
A
Mateo
Jacques L
JL
Zakin