Preparation of highly stable and ultrasmooth chemically grafted thin films of chitosan
Cyrielle Garreau, Leonardo Chiappisi, Samantha Micciulla, Isabelle Morfin, Stéphane Trombotto, Thierry Delair, Guillaume Sudre
Abstract
an optimized water-temperature treatment (WTT). The formation of a grafted chitosan network insoluble in acidic aqueous media (pH 3.5) was evidenced and the films were stable for at least 2 days at pH 3.5. The film morphology and the swelling behavior were characterized by atomic force microscopy (AFM) and neutron reflectivity, which showed that the film roughness was extremely low. The physical cross-linking of the films was demonstrated using infrared spectroscopy, dynamic mechanical analysis (DMA) and wide-angle X-ray scattering (WAXS). Finally, we show that the swelling behavior of such films was largely influenced by the environmental conditions, such as the pH or ionic strength of the solution.