An Onion Phase in Salt‐Free Zero‐Charged Catanionic Surfactant Solutions

No added salt: Transmission electron microscopy and small-angle X-ray scattering studies have shown that uni- and multilamellar vesicles with radii of 25.5 and 366 nm (see schematic diagram; the hydrophilic cation/anion groups are shown as green spheres and the hydrocarbon chains in blue), respectively, are formed from trimethyltetradecylammonium hydroxide and oleic acid in water. The multilamellar phase consists of seven bilayers.