A novel approach to electrospinning of pristine and aligned MEH-PPV using binary solvents

Pristine and aligned electrospun fibers of poly[2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV) have been fabricated by electrospinning. The key to success was using a binary solvent system, in which a poor solvent was introduced to increase interchain interactions of MEH-PPV. At the same time, the poor solvent should have a low surface tension and high conductivity. The emission spectra of pristine MEH-PPV in electrospun fibers, spin coating film and dilute solution were acquired and analyzed. The emission anisotropy of aligned electrospun fibers was investigated by polarized emission measurement. For pristine MEH-PPV fibers, the emission anisotropy is 0.47 at emission peak, indicating alignment of MEH-PPV chains along the electrospun fiber axis. For MEH-PPV/poly (epsilon-caprolactone) (PCL) electrospun fibers, the interchain energy transfer in MEH-PPV was significantly depressed. As a result, MEH-PPV/PCL electrospun fibers exhibited a strong blue shift of emission maximum and increased emission anisotropy of 0.66 compared with pristine MEH-PPV electrospun fibers. The ease of electrospinning of pristine MEH-PPV provides new opportunities for its application in unique optoelectronic devices.