Polymer gelatin of type A from porcine skin in powder form was purchased from Aldrich (Milwaukee, USA).
Dissolving solvent of TFE is a product from Fluke.
To prepare spinning solutions, the gelatin was dissolved in TFE stirring at room temperature for 6 h to make transparent solutions. Different gelatin concentrations of 2.5, 5.0, 7.5,10, 12.5, and 15% w/v were prepared in order to investigate spinnability, fiber morphology, and mechanical performance of the resulting ultra fine fiber mats. Here, for instance, 10% w/v means that 1 g of gelatin powder was mixed with 10 ml of TFE solvent.
The polymer and the solvent were used as provided without further purification.