Hot electrospinning of polyurethane fibres

Several polyurethane solutions of the same composition but varying temperature (25, 50, 75 and 100 °C), were subjected to an electric field whilst flowing through a conducting nozzle. All other typical electrospinning parameters (applied voltage, medium infusion rate and collecting distance) were kept constant. The effects of processing solution temperature on the resulting fibre morphologies were assessed using optical and scanning electron microscopy, and were also correlated with solution properties (surface tension, viscosity, electrical conductivity and density). It was observed that increasing the solution temperature leads to a significant reduction in the mean diameter and size distribution of the resulting fibres. Increasing the temperature from 25 to 100 °C enabled the reduction of the mean fibre diameter from 2.5 μm to 1.2 μm. The T m value of resulting fibres generally increased as the solution processing temperature increased suggesting a change to the orientation of polymer chains in the overall structure.