Structure and properties of soft organic-aqueous interfaces

The interfaces formed by water and aqueous solutions with organic soft matter play an important part in nature and technological applications. Good examples are provided by water in contact with surfactants, self-assembled monolayers, polymers, biomembranes, and other biological matter. A characteristic feature of most soft organic-aqueous interfaces is a deep interpenetration of the aqueous and organic phases, resulting in a wide interfacial region that can formally be regarded as an interphase. The anisotropy, inhomogeneity, thermal disorder, and large extension of the interfacial region in width make the structure and properties of such interfaces difficult to study with the available experimental techniques. The situation is particularly complicated in sandwich-like systems, where water or an aqueous solution is nanoconfined between organic phases. This occurs, for instance, when two biomembranes come close together, so that their interfacial regions interact and intersect.