LAUSR

Abstract The micellar solution of a surface active ionic liquid, 1-hexadecyl-3-methylimidazolium tetrafluoroborate (C16mimBF4), with the presence of organic salt sodium salicylate (NaSal) was investigated by rheological measurements and 1HNMR. According to steady-shear viscosity curves, with the increase of NaSal concentration, the zero-shear viscosity η0 firstly showed an increase which meant the gradual formation of wormlike micelles in solutions (the most optimal concentration of NaSal was 4.5 mM), then η0 decreased to the previous value which indicated the wormlike micelles were destroyed. And the results of 1HNMR were further verified the structure transformation. The C16mimBF4/NaSal solution showed special viscoelastic property with the increase of NaSal concentration. When the linear wormlike micelles formed, the mixture solutions had viscosity (G′G″). In the frequency sweep rheological measurements, the curves of G′ and G″ showed two intersections, which indicates the structure of long wormlike micelles is weak and may be cut into short ones at higher shear frequency. Graphical Abstract