Polystyrene (PS) nano-and micro-fibers presenting a fiber-bead structure were obtained by electrospinning. Incorporation of multiwalled carbon nanotubes (MWCNTs) into polymer solutions followed by electrospinning was also performed, thus affording composite electrospun fibers. Scanning electron microscopy (SEM) studies showed that the fiber-bead morphology for PS and the composite fibers changed gradually as the MWCNTs concentration increased, resulting in smooth defect-free fibers. Furthermore, thermogravimetric analysis did not show a significant enhancement in the thermal properties with the addition of the carbon nanotubes. However, the intermolecular interactions between the polymer nano-and micro-fibers and the MWCNTs were investigated through Fourier transform infrared spectroscopy (FT-IR), which revealed that the aromatic ring in the polystyrene matrix was deformed when interacting with the MWCNTs. (C) Koninklijke Brill NV, Leiden, 2012