Preparation Of MEH-PPV/PVP Electrospun Fibers And Investigation Of Their Properties

PPV-like electronic polymers exhibit an excellent photoelectricity characteristic in conductor, luminescence, photovoltage transition, optics nonlinearity, etc. As kind of poly (1-4-phenylene vinylene) (PPV) derivative, poly [2-methoxy-5- (2'-ethyl-hexyloxy)- 1,4-phenylene vinylene] (MEH-PPV) is soluble in common organic solvent compared with PPV, which holds splendid photoelectricity multifunctional characteristic. Nowadays, MEH-PPV has become a research focus in the region of luminescence.Because of the very small diameters, the high specific surface area per unit mass and the large surface-to-volume ratio, nanofibers have manifested many chemical and physical (heat, light-emitting, electromagnetism etc.) special performances, and these fibers are of considerable interests for various kinds of application such as adsorption, filtration, protection and biological medicine. The technologies for the preparation of Polymer nanofibers include electrospinning, sea-island model spinning, molecular spinneret spinning, biologic synthesis, chemical synthesis etc. Electrospinng is an effective method of high efficiency and small waste of preparing polymer nanofibers. Electrospinning is the focus way recently and has demonstrated a large potential.Electrospinning origins from that electrically charged fluid is forced jets in the high voltage electrostatic field. Electrospinning occurs when the electrical forces at the surface of a polymer solution or melt overcome the surface tension and cause an electrically charged jet to ejected. When the jet dries or solidified, an electrically charged fiber remains. This charged fiber could be directed or accelerated by electrical forces and then collected in mats or other useful geometrical forms. The diameters of electrospun fibers are in the range of tens of nanometers to several micrometers.This paper describes the technique of using coaxial electrospinning to generate core-shell structured PVP (Poly vinyl pyrrolidone)/MEH-PPV nanofibers with diameters in the submicron or nanometer range. Compared with the pure MEH-PPV film and bulk, PVP/MEH-PPV fibers show a significant blue shift and have the stronger intensity of fluorescence, it should be due to the prevention of aggregation and high surface area-to-volume or length-to-diameterratios of the electrospun fibers, respectively. Owing to the inner polymer PVP, the morphology of fibers increased that may have wide interesting potential applications in the nanophotoelectron apparatus.Ultrafine polyvinylpyrrolidone (PVP)/ poly [2-methoxy-5- (2'-ethyl-hexyloxy) -1,4 -phenylene vinylene] (MEH-PPV) composite fibers were successfully prepared by electrospinning of PVP/MEH-PPV blend solutions in solvent mixtures of 1,2-dichloroethane/chlorobenzene. Composite polymer fibers with smooth surface were obtained using the solutions in which MEH-PPV's concentration was 1.0(w/t%). Electrospinning of PS/MEH-PPV composite fibers have been reported using an electrospinning method, and the results showed that the MEH-PPV was red-shifted in the composites, but they don't study the different photoluminescent intensity when MEH-PPV in different states. Compared with the MEH-PPV solution and bulk, PVP/MEH-PPV fibers show a significant blue shift, the stronger intensity of fluorescence and the higher surface photovoltage (SPV). As a result, this kind of composite fibers is expected to be applied for the photovoltaic cell and red-light devices such as red LEDs and red flat panel displays.