Color change of electrospun polystyrene/MEH-PPV fibers from orange to yellow through partial decomposition of MEH side groups

The present contribution reports the electrospinning of PS/MEH-PPV fibers with average diameters ranging from 0.165 toL190 mu m from solutions of PS/MEH-PPV (PS/MEH-PPV = 7.5:1, w/w) in 1,2-dichloroethane. With the addition of pyridinium formate (PF), a volatile organic salt, to the PS/MEH-PPV solution, the electrospinnability of the resulting solution is enhanced significantly. Both the fiber diameters and the number of fibers are found to increase, while the number of beads is found to decrease with increasing applied electrical potential, the addition of PF, and increasing aging period of the spinning solution after PF addition. FT-IR analysis shows that approximate to 15% of the MEH side groups are removed from the MEH-PPV component in the fibers obtained from the solution that is left to age for 1 month after PF addition, which corresponds well to the loss of mass of approximate to 7% as observed by thermogravimetric analysis. As a result, partial decomposition of the MEH side groups should be responsible for the observed yellow emission color of the PS/MEH-PPV fibers obtained from the same solution.