Rich aggregate morphologies induced by organic salts in aqueous solutions of a cationic gemini surfactant with a short spacer

Various aggregates, such as spherical and elongated micelles, tubular and rodlike aggregates, as well as vesicles, are induced by adding sodium 2-naphthalenesulfonate (SNphs) or sodium benzenesulfonate (SBzs) into the aqueous solution of a gemini surfactant C12C2C12(Me) (1,2-ethanediyl-bis-(dodecyldimethylammonium bromide)). The aggregate morphology strongly depends on the added amount of the organic salts. Among the various aggregates, the elongated micelle and the tubular aggregate have larger solubilizing capacities than those with the other morphologies. However, SNphs and SBzs cannot induce similar aggregate transitions for the systems of C12CsC12(Me) (s=6, 8, 12). The possible mechanism of these phenomena is proposed based on the results of UV spectra and 1H NMR measurements and the molecular packing geometry rule.