Polymer Confinement in Surfactant Bilayers of a Lyotropic Lamellar Phase

Polymer-Surfactant Mono and Bilayers

“…Our experimental data are concentrated in the region of high surfactant content (from 65 wt% to 85 wt%) where a lamellar Lα phase exists at room tem perature. Several freeze fracture electron microscopy images, taken for various polymer concentrations at several degrees of sulfonation show a well defined lamellar structure and the interlayer distance is in very good agreement with SAXS-determined values [7]. The surfaces exposed by cleavage are mid-sections through the hydrophobic centre of the bilayer.…”

“…Freeze fracture electron microscopy results unequivocally demonstrate that the polymer molecules enter bilayers and remain incorporated inside them for any charge content between 30 and 90 percent. There is a pronounced polymer-surfactant interaction (evi denced from surface tension data) that leads to the deformation of the lamellar structure (evidenced from SAXS data, see [7], The polymer incorporation inside bilayers is the first observation of this kind in a surfactant/water/polymer system. Together with former stud ies on different systems, it illustrates the great variety of possible configurations of polymers chains in lamel lar phases.…”

“…The polymer used has a molecular weight of 250.000 (Mw /Mn = 2) [7]. The behaviour of PSS in water is unusual for polyelectrolytes.…”

“…Experimental data for the binary C12E5/water system are shown with empty circles, full circles correspond to 0.1 wt% of polymer and triangles to 0.3 wt% of polymer. After [7]. surface tension for pure C12E5/water system and with addition of 0.1 wt% and 0.3 wt% of PSS (x = 45%).…”

“…There is a general interest in the basic research on the modifica tion of surfactant self-assembly by the addition of poly mer molecules and the behaviour of such molecules in confined environment. For polymers solubilised into a surfactant lamellar phase various structural models have been proposed, according to which the polymer molecules may be either confined in the water regions [3] and [4], cross between those regions through the bilayer [5], remain partly on the surface of bilayer and partly inside [6], or remain confined inside bilayers [7].…”