SURFACE INTERFACIAL-TENSION DYNAMICS OF VESICLE-FORMING SURFACTANTS

In the present work the dynamics of surface (at the aqueous solution/a ir interface) and interfacial (at the aqueous solution/n-decane interf ace) tensions were studied for diluted aqueous solutions of dialkyldim ethylammonium bromides with alkyl chain lengths of 10 and 12 carbon at oms. These amphiphiles form different kinds of bilayer aggregates in a queous systems, such as small unilamellar vesicles, multilamellar lipo somes and random lamellar L(3) phases, depending on the surfactant con centration. Dynamic tension measurements were performed by drop weight and drop volume methods. It was found that the rate and the character of surface tension equilibration is strongly dependent on surfactant concentration. The data obtained were analysed on the basis of modern theoretical conceptions and the diffusion coefficient values were esti mated using the approach developed by Fainerman et al. (Colloids Surfa ces A: Physicochem. Eng. Aspects, 87 (1994) 61).