Functionalized superhydrophobic biomimetic chitosan-based films

Chitosan has been greatly applied in the fields of biomedicine, biomembranes and food/nutrition because of its nontoxic and biocompatible properties. However, water solubility of chitosan at pH < 5 strongly limits the use of chitosan-based films when pH stability and low water uptake are required in many actual applications. In this work, silyl chitosan, 3,6-O-di-tertbutyldimethyl silyl chitosan, a chitosan derivative, was synthesized and used to prepare extreme water-repellent films in the whole pH range of 1-14 using a phase separation method that exhibit topography with a three-level hierarchical roughness organization. The polymer also allows posterior chemical modification specifically through the amine group, permitting to control the surface chemistry and wettability. This work not only improve the stabilization of chitosan-based films but also demonstrates the possibility of manufacturing polysaccharide-based superhydrophobic surfaces with potential to be used in anti-bacterial substrates, tissue engineering, food industry and other biomedical applications.