Preparation and characterization of water-absorbing gas-assisted electrospun nanofibers based on poly(vinyl alcohol)/chitosan

Water-absorbing nanofibers were fabricated from polyvinyl alcohol (PVA)/chitosan (CS) solution using gasassisted electrospinning with a spinning rate of 180 mu L.min(-1). The gas-assisted electrospinning is a functional approach with desirable productivity compared to typical electrospinning. PVA/CS nanofibrous mats were tailored considering varied volumetric ratios to assess the final structure. The citric acid (CA) was incorporated as the cross-linking agent to make an insoluble nanofibrous structure. The optimal volume ratio of the dope solution was determined to be 70/30 (with 0.05 wt% citric acid). The thermal post-treatment was used to construct polymeric network hydrogels. A set of characterization methods such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), swelling behaviors, as well as rheo-mechanical spectroscopy (RMS) were investigated to assess the resultant nanofibers/hydrogel characteristics. Results indicated that PVA/CS nanofibers with the mean fibrous diameter of about 80 nm demonstrate uttermost water absorption capacity (up to 9,000 % at pH = 5) and high swelling ratio, as well as uniform structure that are found to be a potential candidate for anti-sweat absorber and biomedical applications.