Keynote Talk: Mesostructured Polymer Surfactant Films

Solutions of polyelectrolytes with surfactants show a variety of adsorption behaviours at interfaces. We have exploited this phenomenon to create solid films of polyelectrolyte and surfactant at the air-solution surface, from solutions where the polyelectrolyte is uncharged. In these systems, a self-supporting film containing highly ordered 2D or 3D surfactant mesostructures in a hydrogel matrix several hundred nanometres thick forms spontaneously at the solution surface.1 Our initial investigations focused on films made from polyethylenimine and cationic surfactants and we continue to study film formation mechanisms in this system.2 We have also grown films using a number of other surfactants and polymers, allowing detailed control of film mesostructure and thickness.3, 4 More recently we have also prepared films with similar structures by spray coating of the same aqueous solutions. To improve the film biocompatibility, we have grown films using zwitterionic surfactants which are less toxic than cationic surfactants. The encapsulation and release of hydrophobic species has been studied as a function of crosslinking and mesostructure in these hydrogel films. We are continuing to develop these membranes for potential applications in controlled release5 and as a responsive support for sensor species. Here, I will describe our studies on these films, in particular our work to understand film formation, control the nanostructure in the films, and improve encapsulation and biocompatibility of our materials.
References
1. KJ Edler, A Goldar, T Brennan, SJ Roser, Chem. Commun., 2003, 1724.
2. RA Campbell, KJ Edler, Soft Matter, 2011, 7, 11125.
3. KJ. Edler, MJ Wasbrough, JA Holdaway, BMD O'Driscoll, Langmuir, 2009, 25, 4047
4. MJ Wasbrough, KJ Edler, AM Hawley, JA Holdaway, GJ Price, Soft Matter, 2012, 8, 3357.
5. BMD O'Driscoll, AM Hawley, KJ Edler, J. Colloid Interface Sci., 2008, 317, 585.