Characterization: Electrospun fibers were coated with a
thin gold layer using a sputter coater (Polaron, model
SC502) and their morphology was analyzed using a scanning
electron microscope (SEM, Quanta 650, from FEI) with
an accelerating voltage of 15 kV. Nanofiber average diameter
and the distribution were calculated over approximately
40 fibers using SEM images (5000 magnification)
and Image J software. Differential scanning calorimetry
measurements (DSC) were performed in a Perkin–Elmer
Pyris-1 apparatus at a heating rate of 10 C.min1
. Samples
for the DSC studies were cut into small pieces from the
middle region of the electrospun membranes and placed in
40 mL aluminum pans. All experiments were performed
under a nitrogen purge. The thermal degradation kinetics
of the samples was characterized by thermogravimetric
analysis (TGA) in a Perkin–Elmer Pyris-1 TGA apparatus at
heating rate scans from 10 C.min-1 up to 40 C.min1
performed under a nitrogen atmosphere.
3