We have recently discovered a new method of making solid nanostructured films of water soluble polymers with surfactants. These membranes form spontaneously at the surface of aqueous solutions of the two components, and contain highly ordered arrays of micelles surrounded and bound together by the polymer. The films are robust, can be easily lifted from the interface where they form, and will grow over an arbitrarily large area, the size of the container where they are prepared. Our preliminary experiments have shown that it is possible to incorporate hydrophobic material within the micelle array inside the films. The ability to encapsulate other molecules in these films raises the possibility of using them for sustained release applications to deliver eg drugs, flavours, pesticides etc. In this proposal we will work to develop polymer-surfactant membrane-forming systems to optimise nanostructure formation and encapsulation properties and to map the relationship between polymer and surfactant properties and those of the resulting membrane. This new method provides a simple, cheap and straightforward method to creating large areas of free-standing polymer membranes with encapsulated material and in this proposal we will particularly target formation of the membranes from biocompatible polymers towards potential drug release applications.