Confinement effects on water structure in membrane lyotropic phases

Abstract

The change of the water structure in aqueous solutions of the tri-ethyleneglycol mono n-decyl ether (C 10E 3) was studied by micro Raman scattering. The results obtained on the O–H stretching band show that the behavior of the hydrogen bonding (H-bonds) water network can be used as a probe to follow the lamellar (L α) to sponge (L 3) phase transition. In the lamellar phase, the stack of the surfactant molecules aggregated into a two-dimensional structure (membrane) acts as a soft confinement system for the H-bond water network of which the regular tetrahedral structure is perturbed. The change of the planar organization of the membranes to a highly disordered and infinite array of bilayers in the sponge phase amplifies the surface of contact between amphiphilic surfactant and water molecules which drives a strong disruption of the regular tetrahedral H-bonding water network.