Microemulsions as model fluids for enhanced oil recovery: dynamics adjacent to planar hydrophilic walls

Abstract

Abstract. After the dynamics of microemulsions adjacent to a planar hydrophilic wall have been characterized using grazing incidence neutron spin echo spectroscopy, the model of Seifert was employed to explain the discovered acceleration for the surface near lamellar ordered membranes. Reflections of hydrodynamic waves by the wall -or the volume conservation between the membrane and the wall -explain faster relaxations and, therefore, a lubrication effect that is important for flow fields in narrow pores. The whole scenery is now spectated by using different scenarios of a bicontinuous microemulsion exposed to clay particles and of a lamellar microemulsion adjacent to a planar wall. The Seifert concept could successfully be transferred to the new problems.

Polymer enrichment decelerates surfactant membranes near interfaces

“…(A4) with the expression from Seifert [Eqs. (9), (10), and (16) in Ref. [24]], where the distance to the flat walll determines how the undulation mode spectrum is modified:…”

“…The first microscopic characterizations of three-component microemulsions near planar surfaces have been carried out in terms of analyzing structure [8] and dynamics [9,10]. Microemulsions consist of water and oil and the mediating surfactant, which leads to macroscopically homogenous fluids.…”

“…Bicontinuous microemulsions consisting of water and decane and the nonionic surfactant C 10 E 4 with the same concentrations as in Refs. [8][9][10] were used. For the structural analysis, we used a sample consisting of 41.5% D 2 O and 41.5% C 10 H 22 (volume fractions).…”

Interfaces modify the undulation spectrum of bicontinuous microemulsions

“…The dynamics of bicontinuous microemulsions with added small clay particles (Laponite, diameter ∼ 80 nm) showed no change of the dynamics [12]. Recently, the same experiment has been repeated with much larger clay particles (Nanofil, diameter > 200 nm).…”

“…Figure 5 shows the intermediate scattering function of a pure microemulsion and a microemulsion with large clay particles. It was attempted to match the average scattering length density of the oil/water mixture of the microemulsion in film contrast, where only the C 10 E 4 -surfactant layer remains visible against the rest of the components h-decane (33%)/d-decane (67%), H2O(30%)/D2O(70%), as it has been made successfully with the laponite particles [12]. The more natural clay resulted in a less well matched system as for the Laponite case, as can be seen in the remaining plateau value at the highest q-value 0.18Å −1…”