From the SEM images shown in Figure , it is evident that each polymer sample exhibits a heterogenous and porous surface morphology. PN possesses irregular agglomerated short fibrous growth patterns (Figure ). The strands length is ~1 m on average, and the width is between 300-500 nm. The interwoven strands form small voids of similar size. PNZ and PNF exhibit a much denser microstructure, which consists of several micrometer-sized particles that are strongly agglomerated (Figure and). Particularly noticeable for PNF is the pronounced agglomeration of the composite, which can be attributed to the magnetic properties of the Fe2O3 nanoparticles incorporated in the polymer structure .