Small-angle light scattering in dense microemulsions, transition from droplet to bicontinuous phase

Abstract

(ricevuto il 28 Ottobre 1994)Summary. --We have performed extensive small-angle light scattering (SALS) measurements on a three-component microemulsion (AOT/decane/water) as a function of the dispersed phase concentration and the temperature. All samples have a water/AOT molar fraction w --40.8. Such a system presents a very complex phase diagram with many structural configurations. With the SALS technique, we have been able to observe all the phase separation lines. In particular we give details on the system structure on the percolation phenomenon and on the bicontinuous phase recently observed. In particular we show that the percolation is driven by a long-scale aggregation between microemulsion droplets.

Aggregate Structure and Dynamic Percolation in Microemulsions

“…2.16, divides the one phase droplet region below phase separation temperature into a conducting and a non-conducting droplet phase. It is important to note, that the percolation line through the T -φ-plane is a dynamic line which surprisingly does not affect the droplet structure [5,65]. It is quite an unique feature of AOT microemulsions that the droplet phase is preserved up to droplet concentrations of even 70 vol% (which are possibly present within a droplet cluster) without losing the spherical symmetry.…”