Electrospinning of polycaprolacton/chitosan core-shell nanofibers by a stable emulsion system

Electrospun core-shell structured nanofibers have got wide attention due to their excellent properties and potential applications. Encapsulated CS in PCL to form the core-shell structured fibers would be a festival way to expanding the applications of biopolymers. In this work, the electrospun core-shell polycaprolacone/chitosan (PCL/CS) composite nanofibers were prepared by a stable emulsion system. Different from other reported works, the surfactant-free and low toxic water-in-oil emulsion was selected to form the electrospinning precursor. The high stability of the emulsion was achieved by adjusting the volume ratio of the solvents and the concentration of the polymers. PCL/CS fibers with different core to shell ratios were obtained via the adjustment of the concentration of CS and PCL in emulsion system. The distribution of the composition in the fibers was analyzed by FT-IR, XRD, EDS, XPS and WCA. Further, intact ultrafine CS fibers with a mean diameter of 143 ± 49 nm could be obtained after the removal of PCL shell, indicating the low diffusivity between core and shell solutions during emulsion electrospinning process. This study provided a promising method to fabricate natural polymer fibers which were difficult to electrospin.