Study of the micelle-to-vesicle transition and smallest possible vesicle size by temperature-jumps.

We have investigated the temperature induced micelle-to-vesicle transition in a binary non-ionic surfactant/water system, for which the spontaneous curvature decreases with increasing temperature. Temperature jumps with variable rate were performed in a microwave oven, from a micellar phase at 5°C to a lamellar phase region at 35°C, passing a liquid-liquid two phase region where dilute and concentrated micellar solutions coexist. It is shown that the obtained vesicle size decreases with increasing heating rate through this two phase region.