Morphology and photophysical properties of light-emitting electrospun nanofibers prepared from poly(fluorene) derivative/PMMA blends

Light-emitting electrospun (ES) nanofibers with diameters of 250-750 nm were successfully prepared through the binary blends of polyfluorene derivative/poly(methyl inethacrylate) (PMMA) using a single-capillary spinneret. The studied poly(fluorene)s included poly(9,9-dioetylfluoreny-2,7-diyl) (PFO), poly[2,7-(9,9dihexylfluorene)-alt-5,8-quinoxaline] (PFQ), poly [2,7-(9,9-dihexylfluorene)-alt-4,7-(2,1,3 -benzothiadiazole)] (PFBT), and poly [2,7-(9,9-dihexylfluorene)-alt-5,7-(thieno[3,4-b]pyrazine)] (PFTP). The transmission electron microscopy (TEM) studies showed that uncontinuous fiberlike structure was obtained at the low PFO/PMMA blend ratio but became a core-shell structure at a high PFO blend ratio. The poorer solubility of PFO in chloroform than that of PMMA probably forced it to be solidified first as the fiber core. Besides, a porous surface structure on the PFO/PMMA blend fibers was observed due to the rapid evaporation of the chloroform solvent. The PFO aggregation domain in the ES fibers was much smaller than that in the spin-coated films and led to higher photoluminescence efficiency. Uniform ES fibers produced from the binary blends of PFO/PMMA, PFQ/PMMA, PFBT/PMMA, and PFTP/PMMA exhibited the following luminescence characteristics (peak maximum (nm); color): 443, blue; 483, green; 539, yellow; 628, red. The present study demonstrates that full color light-emitting ES nanofibers could be produced from the binary blends of polyfluorene derivative/PMMA.