pH-sensitive nanostructured architectures based on synthetic and/or natural weak polyelectrolytes

This study aims to evidence the influence of polyelectrolytes structure and the number of double layers on the properties of some new nanostructured architectures formed by layer-by-layer self-assembly of complementary weak polyelectrolytes on planar surfaces. For this purpose, we used chitosan and poly(allylamine hydrochloride) as polycations, and poly(acrylic acid) and poly(2-acrylamido-2-methylpropanesulfonic acid–co-acrylic acid) as polyanions. To get a direct image on the polyelectrolyte multilayers formation and properties, gravimetry, infrared spectroscopy, and atomic force microscopy have been used. The capacity of the polyions to overcompensate the complementary polyions charges, and thus to influence the swelling degree in water of thin films, was strongly influenced by the chain structure and flexibility. A special attention was paid to the responsiveness of the new composite materials to the pH of the swelling environment.