Water resistance of chitosan-based composite film induced by dopamine and glyoxal

Abstract

Herein, a chitosan composite film based on a biomimetic strategy through the “brick–mortar” structure design was prepared. The glyoxal induced polymerization of dopamine acted an excellent adhesion between the “brick” and “mortar” (montmorillonite and chitosan). As a result, the resultant film presented an excellent water resistance towards acidic and alkaline solutions (pH 2, 4.5, 9 and 11) even after 24 h, with the undestroyed and intact shape. The dopamine or glyoxal content had a great influence on the water resistance, especially in the acidic media of pH 2. SEM and AFM results showed that the chitosan, montmorillonite, and dopamine formed a homogeneous film. Meanwhile, the dopamine dosage produced an obvious influence on the surface morphology of composite film. XRD patterns exhibited that in the chitosan composite film, the chitosan, montmorillonite and dopamine rearranged. At the suitable additions of dopamine or glyoxal, the chitosan composite film could keep intact shape, showed by the swelling results. The dynamic contact angles decreased with the enhanced montmorillonite or glyoxal dosages. This facile approach provided novel method for promoting the application potential and performance of chitosan-based composite film.