Nanoscum: solid nanostructured films at the air–water interface

The formation of solid films at the air-solution interface is a common phenomenon, however, these films have largely not been explored from a materials point of view. In solutions containing inorganic species with surfactants these films, which can be several microns thick, have a highly organised nanoscale structure aligned with respect to the interface. More recently similar polyelectrolyte-surfactant membranes have been prepared which show similar nanostructures encapsulated within the film. The current state of understanding of these films is reviewed, and the links between two apparently disparate systems are highlighted.