Aggregation behavior in aqueous solutions of a new class of asymmetric bipolar amphiphiles investigated by surface tension measurements

Two series of amphiphilic derivatives of lactose have been synthesized. Ten siometric investigations of the critical micellar concentration (CMC) and t he area per molecule at interface (calculated by the Gibbs equation) of aqu eous solutions were performed. The values measured depend on the number of methylene groups of the alkyl spacer n and that of the side chain m as well as on the ionic strength and temperature. The results show a behavior clos ely related to that of gemini surfactants: (1) self-assembly phenomena occu r at concentrations below 1 mM, (2) at constant n log CMC increases linearl y with higher m, and (3) the influence of the temperature on the aggregatio n phenomenon is comparable. (C) 2001 Academic Press.