Formation and characterization of core-sheath nanofibers through electrospinning and surface-initiated polymerization

Novel core-sheath nanofibers, composed of polyacrylonitrile (PAN) core and polypyrrole (PPy) sheath with clear boundary between them, were fabricated by electrospinning PAN/FeCl₃·6H₂O bicomponent nanofibers and the subsequent surface-initiated polymerization in a pyrrole-containing solution. By adjusting the concentration of FeCl₃·6H₂O, the surface morphology of PPy sheath changed from isolated agglomerates or clusters to relatively uniform thin-film structure. Thermal properties of PAN-PPy core-sheath nanofibers were also characterized. Results indicated that the PPy sheath played a role of inhibitor and retarded the complex chemical reactions of PAN during the carbonization process.