Core–Shell Structured\nPEO-Chitosan Nanofibers\nby Coaxial Electrospinning

Abstract

Core–shell structured PEO-chitosan nanofibers\nhave been\nproduced using a coaxial electrospinning setup. PEO and chitosan solutions,\nboth in an aqueous acetic acid solvent, were used as the inner (core)\nand outer (shell) layer, respectively. Uniform-sized defect-free nanofibers\nof 150–190 nm diameter were produced. In addition, hollow nanofibers\ncould be obtained subsequent to PEO washing of the membranes. The\ncore–shell nanostructure and existence of chitosan on the shell\nlayer were confirmed by TEM images obtained before and after washing\nthe PEO content with water. The presence of chitosan on the surface\nof the composite nanofibers was further supported by XPS studies.\nThe chitosan and PEO compositions in the nanofibrous mats were determined\nby TGA analysis, which were similar to their ratio in the feed solutions.\nThe local compositional homogeneity of the membranes and the efficiency\nof the washing step to remove PEO were also verified by FTIR. In addition,\nDSC and XRD were used to characterize the crystalline structure and\nmorphology of the co-electrospun nonwoven mats. The prepared coaxial\nnanofibers (hollow and solid) have several potential applications\ndue to the presence of chitosan on their outer surfaces.