Electrical conductivity and percolation phenomena in water-in-oil microemulsions

Abstract

We study static electrical conductivity of water-in-oil microemulsions in the single-phase region. Below the percolation threshold, the data can be interpreted in terms of a Auctuating-charge model.Above the percolation threshold, in the lamellar region, the conductivity is consistent with randomly oriented~ater layers separated by surfactant sheets. The loci of the percolation thresholds are measured for diA'erent values of water to surfactant molar ratio and explained in terms of a continuum percolation model.

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

“…1) [5]: there is a cloud point curve separating the one-phase and two-phase microemulsions, including a lower consolute critical point (To N 40 ~ and r = 0.1) [4]. For high concentrations, r > 0.4, we have observed L~ (lamellar) and the oil-in-water phases below the two-phase region [6]. In particular, boundary lines separating the oil-in-water, the lamellar and the water-in-oil regions cross the cloud point curve at r -0.4.…”

Aggregate Structure and Dynamic Percolation in Microemulsions

“…If furthermore the temperature dependence of K (T ) is expanded in a Taylor series the percolation temperature T p and phase transition temperature T c can be calculated in a T -φ phase diagram [64]. In particular this gives the opportunity to add a new phase line in the phase diagram of the T -φ-plane [59,64], cf. Fig.…”

How to calculate phase diagrams for microemulsions — a simple rule

“…Fig. 4) solely depends on the volume fraction of the enclosed phase and of surfactant [19,[46][47][48]. It is independent of temperature and solely determined by the prescribed volume and surface area of the droplets.…”