A TIME-RESOLVED SMALL-ANGLE NEUTRON-SCATTERING STUDY OF THE MICELLE-TO-VESICLE TRANSITION

Amphiphilic molecules spontaneously self-assemble in solution to form a variety of aggregates. While significant progress has been made in t he understanding or equilibrium properties such as the sequence of str uctures as a function of the solution composition, limited information is available about the existence of non-equilibrium or metastable sta tes and the pathway and kinetics associated with the structural transi tions observed. Aqueous mixtures of lecithin and bile salt exhibit a t ransition from polymer-like mixed micelles to vesicles upon dilution. Here we present a time-resolved study of this transition using light a nd small angle neutron scattering experiments. We demonstrate that it is possible to follow the temporal evolution of the aggregate structur e and obtain detailed information even on molecular length scales.