Ultrathin polymer coatings by complexation of polyelectrolytes at interfaces: suitable materials,structure and properties

The article presents the state‐of‐the‐art of alternating physisorption of oppositely charged polyelectrolytes, the so‐called “layer‐by‐layer” method or “electrostatic self‐assembly” (ESA), for the preparation of thin polymer coatings. In comparison to other, more established self‐organization techniques, this recent method is distinguished by its simplicity, versatility, and speed. In particular, the tendency for self‐healing is unique. Emphasis is given to the role of the molecular structure of the polyelectrolytes, and to the nature of the support. Also, various parameters for the preparation of multilayer films are highlighted, which are very important due to the kinetic control of the build‐up process. The structure of the resulting coatings, their quality and stability, chemical reactions in the films, and potential applications are discussed.