Morphology of Chitosan-Based Hollow Cylindrical Materials with a Layered Structure

Abstract

The surface morphology and supramolecular structure of chitosan-based hollow cylindrical structures (microtubes) obtained by wet and dry–wet spinning were studied with the use of salting-out agents of various chemical nature by scanning electron microscopy. All samples are characterized by a layer-oriented porous structure, whose morphological features are determined by the spinning process and the chemical nature of the reagent for the polymer conversion polysalt → polybase reaction. An explanation of the formation of this layered structure is proposed within the framework of the Liesegang phenomenon. The influence of the nature of the salting-out agent on the mechanism of the chemical reaction and the polymer material structure was assessed. All microtube samples are shown to be characterized by anisotropy of their mechanical properties. When stretching in the longitudinal direction, an almost linear load–strain relationship is observed with the elastic component predominance, while stretching in the transverse direction yields a nonlinear one with the predominance of plastic deformation.