Electrospun Chitosan Nanofibers: Influence of Temperature and Humidity on the Structure and Chemical Properties

Chitosan is one of the most difficult polymers to use in electrospinning, and the influence of environmental parameters on the electrospinning process has not been thoroughly investigated, making it particularly difficult to obtain uniform fibres with high reproducibility. This study examines the influence of relative humidity (30%–60% RH) and temperature (20–40 °C) on electrospun chitosan fibres, using trifluoroacetic acid as the solvent. Field emission scanning electron microscopy (SEM), attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy, and differential scanning calorimetry (DSC) were employed to evaluate the morphological, chemical, and thermal characteristics of the resulting fibrous structures, respectively. Although ATR-FTIR analysis indicated that the chemical composition remained consistent, FESEM revealed that variations in the temperature and relative humidity during electrospinning led to changes in the fibre diameter, pore size, and porosity. Furthermore, DSC demonstrated that variations in temperature and humidity during chitosan fibre production influenced the melting enthalpy, glass transition temperature, crystallinity temperature, and melting temperature. Ultimately, the optimal temperature (30 °C) and humidity (50% RH) conditions were determined for the given electrospinning parameters.