Zn²⁺-Induced Vesicle Formation

Zn 2+ -induced vesicle formation has been studied for the first time in aqueous mixtures of tetradecyldimethylamine oxide (C 14 DMAO) and zinc 2,2-dihydroperfluorooctanoate [Zn(C 6 F 13 CH 2 COO) 2 ]. The charged vesicle phase without any cosurfactants was prepared in the aqueous mixtures. The charged vesicle phase has interesting rheological properties. This ionically charged vesicle phase is not shielded by excess salts because of salt-free aqueous solutions. Such a vesicle phase is important for many applications where cosurfactant is not used. A cationic/anionic surfactant C 14 DMAOH + - OOCCH 2 C 6 F 13 system could be produced from C 14 DMAO/Zn(C 6 F 13 CH 2 COO) 2 mixtures because the zwiterionic surfactant C 14 DMAO can be charged by the H + released from H 2 S to a cationic surfactant and Zn 2+ is precipitated. After ZnS particles are removed from the cationic/anionic surfactant solutions, the finally mixed sample does not contain excess salts as do other studied cationic/anionic surfactant systems. The sample is a birefringent Lα-phase and consists of unilamellar and multilamellar vesicles. The novel vesicle reproduction route should provide a new method to prepare nanoscale particles.